Thursday, May 5, 2016

Applications of Serial Homicide Data: Killers in Pairs


Presented at the Confronting Homicide in a Changing World Seminar, WI -- April 7, 2016

Yes, that’s me in the first picture, looking like I had everything figured out back in 2005. What I came to realize was that everything I knew about serial murderers was based on stereotypes and myths. After long term exposure to Silence of the Lambs and the Profiler TV show, I had fallen victim to the serial murder entertainment machine. My attitude began to change after more than a decade spent studying serial homicide in Boston. What I thought I knew about serial murder would be consistently challenged after watching the offenders pictured here earn this classification in ways not historically associated with serial murderers. 

With this presentation, we hope to help you begin to understand a bit about the modern serial murderer, specifically those that function in partnerships. I will provide some preliminary findings of my analysis looking at the subset of killers that operate in pairs. 

So where does all of this information come from? To address the issue of definitional discordance, the Serial Homicide Expertise and Information Sharing Collaborative was built with the purpose of bringing together a team of researchers to share their serial homicide data and synchronize collection efforts. In 2012, nine datasets were combined with the Radford Serial Killer Database, strengthening our initiative to create the first national serial murder database. The overall goal of this effort is to encourage further empirical studies, allowing users the option to apply the definition they choose, rather than forcing a specific one on them.

Alongside this effort, I co-founded the Atypical Homicide Research Group which is an active network of one hundred academic researchers, law enforcement professionals and mental health practitioners that allows members to communicate over a private and secure email listserv setup through Northeastern University. The mission of our group is to collaborate to come to a greater understanding of atypical homicide and sexual violence through the exchange of ideas, anecdotes and research. This community was established with the purpose of bridging the gap between current thought and practice through open communication, informed discussion and information sharing. Our secondary objectives are to facilitate the dissemination of research materials, solidify partnerships and foster connections amongst one another while building professional relationships on a foundation of trust and mutual respect. Most of us involved in these efforts call it simply ‘the collaborative’.
When assembling this presentation, there were reports in the news that "Night Stalker" Richard Ramirez may have had help in committing at least one of his murders. There was also a story about a still unnamed 16 year old killer in Brazil that murdered 11 people along with his accomplice. With these killings in mind, we thought it was important to use the database to focus on killers in pairs because it is a neglected area of research. 

As Jenkins notes, the study of teams is important because the existence of multiple killers during the same event can complicate personality profiling. But what is a team? Teams are made up of individuals that come together to accomplish a task by combining resources and sharing ideas. While dynamics between people make the topic a much more complex issue, the basic tenant is that members agree on the methods used to achieve a goal. Goals can be pro-social or nefarious but the same concepts of bonding come into play: loyalty, trust and acceptance. Members are not always like minded but for a pairing to work, one must either agree with or eventually concede to the others point of view. Most of us have heard about the dominant and submissive relationship and nowhere is that more apparent than in the world of serial murder. 

I will be discussing only those multiple murderers that operate in a pair mainly due to the limited nature of data on groups, a byproduct of media sources tending to focus on the primary one or two actors and overlooking the many other participants. As a result, I have excluded gang, cult and crime syndicate activity because the introduction of a third party transforms a pairing into a group and changes the dynamic between two people. These groups often have steep entrance and exit requirements and consequences and limited options for independent decision making Excluding those other than pairs allows us to focus on unwavering partnerships. In larger groups, relationships tend to be tenuous and accomplices are oftentimes interchangeable.

A pairing of serial murderers, on the other hand, represent individuals that are often like minded and form a group out of joint desires to cause harm to others or to take from them what isn’t theirs. Serial killer partnerships benefit from dispensing with the pleasantries that pro-social people use to get others to help them. Although they do not always possess the same skills and abilities, each contributes what they can to ensure the success of the other. The one drawback of participating in a pairing is that the stakes are far greater if one is captured since the concepts of loyalty and trust are often abandoned quickly as one killer cooperates to make a deal with law enforcement before the other does. Oftentimes, though, sharing these risks serves to enhance the bond between the pair.
Most of us will be familiar with these faces. We have pictured here Alton Coleman and Denise Brown, Leonard Lake and Charles Ng, Douglas Clark and Carol Bundy, Kenneth Bianchi and Angelo Buono. In the second row we have Ray and Faye Copeland, Alvin and Judith Neelley, Charlene and Gerald Gallego, Henry Lee Lucas and Ottis Toole. The third row pictures Michael and Thomas McCormick, Martha Beck and Raymond Fernandez, Gary and Thaddeus Lewingdon and Lawrence Bittaker and Roy Norris.

These pairings demonstrate that even serial killers need connections to others for one reason or another. Whether it be a significant other, a family member or a friend or acquaintance, serial murderers have found partners in nearly every iteration of human relationships since the beginning of the phenomenon hundreds of years ago. Pairing up has the advantage of reciprocity and provides someone to trust, to accept them for who they are, to hold them accountable and spur them forward, to help them overcome their fears and apprehension, someone to collaborate with and devise new methods of destruction, someone to provide a connection to grander goals and ideals and to share their desires freely, someone to share the logistical burden of decision making and the blame when things happen against plans. Partners bring each other’s strengths to the forefront. Some have said that killing with another forms the deepest type of bond and that they could not have achieved their destiny without the push the other provided them. Interestingly enough, many of these reasons are the same as why we all engage in pro-social paired relationships. 

But as the conference name indicates, we must confront homicide in a changing world. The remainder of this presentation will be dedicated to the next crop of serial murderers and how they function together as partners to accomplish their goals. 

But how do these killers in pairs compare to solitary serial murderers? Gurian (2013) states that the number of partnered homicides is lower than those committed by solo male offenders. The Radford SKDB confirms that finding in that it contains information on 2,743 US based offenders with 2,095 (76%) of those murderers operating alone, 358 (13%) partnering with an accomplice and 290 (11%) being members of a team with three or more offenders. In total, 648 or 24% of offenders operated as part of a partnership or team. What we found was that the solo offenders represented 76% of the database and killed 84% of the total victims while the paired and grouped offenders represented 24% of the database and killed 16% (1,589) of the total victims. What is interesting is that of that 16%, paired offenders murdered 9% of total victims while grouped offenders killed 7%.

According to White (2014), partnered and lone serial killers differ on several psychologically important characteristics. Serial killers with a partner were less psychiatrically disturbed but more sexually deviant and brutally sadistic. They were less often found to be introverts in adulthood and less often had a major precipitating event prior to the murders. Hickey agrees and states that solo offenders were prone to report feelings of rejection more than team serial offenders and that they cause greater destruction than team killers. Having more than one offender involved did not increase the number of victims per case. 

Hickey’s finding makes sense because an offender operating in a team would need to be open to sharing the experience of murder and confiding in another as apposed to the generally secretive solitary offender. In regards to psychopathy, Joudis writes that the sexual homicide offender would likely encounter significant challenges when attempting to find a co-perpetrator who shares the same extreme deviant interests and can be trusted to share in such activities. Joudis writes that these types of killings were exceedingly likely to be committed by a sole perpetrator as psychopathic individuals are unlikely to cooperate with one another. It seems more likely that a psychopathic individual who plans a murder might recruit an easily manipulated accomplice who could assist in attaining access to victims or who could later serve as a scapegoat for the planned criminal activity. 

With regard to multi-perpetrator homicides, the more psychopathic men tend to select victims of a younger age, to engage in illicit drug use, and to inflict violence for the purposes of causing the victim pain. Given their interpersonal deficits and manipulative tendencies, psychopaths may utilize co-offenders in unique ways. For example, whether through grooming, manipulation, threats, or mimicry, a psychopathic offender influences his non-psychopathic accomplice to commit more gratuitous violence than the partner would have if he had acted alone. This would not account for why accomplice-assisted homicides are often instrumental as the Radford database shows is overwhelmingly the case. Perhaps this is a clue that the majority of partnered serial homicide offenders are not psychopathic. 

As this slide shows, Jenkins, Jones and Gurian have tried to classify serial murderers that function together. Jenkins calls research on killer teams the most obscure area of the field as none of the current co-offending research examines the interpersonal dynamics that permit an offender to recruit allies. Criminologists often lack the background in organizational behavior necessary to appreciate the complex interplay between individuals commonly thought to function alone. 

What we do know is that cooperation involves a broad spectrum of types and degrees of participation. Hickey notes that not all offenders share equally in the thrill or the same motivations or abilities for killing. For this reason, most partners fit into one of three roles that aid the Principal Offender: the Enlisted Accomplice, the Witting Facilitator and the Idle Witness. Jenkins states that those that did not participate in the murder can still create the setting by influencing the primary offender with their attitude. Gurian (2011) noted that passive participation helps legitimize the killing in the principal offenders mind. 

Jenkins believes that partners in dyads found mutual support and encouragement in the other, rejecting the attitudes of wider society and establishing their own world and values. Joudis writes that the loss of individuality in a pairing leads that person to behave in primitive and irrational ways. Gurian (2013) believes that partners operate symbiotically and contribute to each other’s wish for power and share tasks to neutralize feelings of responsibility. Gurian states that partnerships are based on interdependency where unthinkable risks are possible with likeminded individuals. White (2014) believes that the presence of a partner results in less guilt when partners feed off of each other and exhibit more deviant behaviors while they try to outdo each other. Fox thinks there is a special chemistry and a bond of loyalty or love that ignites a willingness to engage in behavior they may never have tried alone. It is not unusual for one to play a dominant role, inspiring the partner to go along for the sake of the relationship. The insanity is located in their relationship rather than in their minds or personalities. Hickey states that partnered homicide is both participation and spectator event where inhibitions and fears dissipate and power is gained by observing, convincing or enticing another take a life. This can bring as much gratification as performing the act themselves. To some partners, killing first became acceptable and then desirable, while others were anxious to become involved but then became killers because of another’s influence. Much like some relationships among non-killers, those of serial murderers are built on deception, bravado and intimidation and nurtured through coercion and persuasive techniques. 

The last image on the slide shows that gang members are not significantly represented among serial homicide offenders as the prevalence of gang members among normal homicides at 10.7% was nearly equivalent to the combined prevalence of the abnormal homicide types at 11.2%. This was important for us to know as we were worried about altering the data by excluding them from the analysis.

One of the main questions driving my research into this area was whether or not offenders differed in their degrees of participation over their series because, as Jenkins states, police can fail to link murders due to differing degrees of participation by “allied” offenders over the course of a series. I wanted to know what percentage of offenders were likely to have killed without a partner and how many would never have killed alone. 

I measured variation by looking at the victim age variable where detailed records were kept of which offender was responsible for the death of which victim.

Where information was available, I found the majority of the 290 offenders that operated in pairs engaged in the same level of participation as their partner (198) at 68%. 32 percent did differ in their level of engagement. These 92 offenders formed 46 pairings. 38 of these pairs had one offender that was responsible for all of the variation; six pairs saw both offenders being responsible for the variation; and two pairs had both offenders vary on all victim counts, suggesting that they watched the other commit the crime. 

Of the 46 pairings, 74% (34) had variation in when their series began and ended. The variation was typical in the early stages of the offender’s series with 20 pairs having a different start date than their partner. 9 pairs had a different end date than their partner. 5 pairs had variation in both their start and finish dates. These instances represent offenders that were killing before they met their partner and those that continued killing after their partner was captured or died. 

Of the 46 pairings, 12 (26%) pairs did have variation in the number of victims that they killed but shared the same start and end dates. These pairs represent instances where the offenders traded off between who would kill the victim.

In almost half of the cases, the difference in victim counts between co-offending serial murderers with variation sat at 1 victim. 

As you will see over the next few slides, I have used the Radford database to generate some descriptive statistics to help us figure out what types of offenders partner up and how this data compares to the current research in the field. I have collected information on all offenders and further break that information across pairings, covering mixed male/female pairs, male/male and female/female partners and then those where there is variation in the victim count. For comparative purposes, I have selected the top 50% and displayed this information in the charts with a number followed by a percentage. Those numbers represent the count of offenders or pairings and their share of the database is represented by the percentage. The first chart here shows demographics on the individual offenders in the cohort whereas the other two charts break out the data by pairings.
White, Fox and Levin state that 20.8% of serial murderers kill with partner while Hickey’s data was 26 percent. Radford contains information on 648 offenders operating as part of a partnership or team, or 24% of the total database.  

Hickey states that males make up 76% of the data on partners and females represent the remaining 24%. Radford is similar in showing that males are present 83% of the time while females show up in 17% of cases. Hickey shows that Caucasians populate the data 55% of the time while African Americans hold 38% of the share. The Radford data is similar in that Caucasians represent 61% and African Americans 32%. According to Gurian, the average age of men in all partnered groups is 27 while average age of women in partnered groups is 29 matching the Radford data exactly. The Radford data shows only a gap of one year between mixed pairs, a surprising finding since Fox and Levin state that in exactly half of cases, one of the partners is much older than the other and dominant. According to the Radford data, partners are the same age in 9% of cases and 46% of the time, offenders are less than 5 years apart in age. 28% of the time there is a five to ten year gap between partners. Males are older than their female counterparts 69% of the time. 

Before we get into how this data compares to the literature, I should mention that the Multi descriptor under victim type encompasses victims killed on the street be it criminals or prostitutes, to hitchhikers, hospital patients, families and home invasion murders and Employees and Customers. The Young descriptor under victim age encompasses children and adolescents while the varied descriptor covers a wide range of ages from teenagers to middle aged adults. 

The Radford data matches Hickey and Gurian’s almost exactly in that 51% of partnered offenders murdered both males and females. The Radford data also shows that 67% of partners murdered at least one female. Where the data diverges is in looking at the victim’s ages. Hickey states that team offenders were least likely to select teenagers and children as victims but the Radford data shows that partners murdered victims under the Varied category, which includes teenagers and young adults, half of the time. Gurian stated that the mixed-sex partners were more likely to murder adult and teen female strangers but the Radford data shows they were more likely to murder a mixture of male and female teen to middle aged members of the general public.

Under Motives and Methods, the Multi descriptor under the Method Count variable encompasses the pairs that utilized any combination of the following methods over the course of their series: Bludgeoning, shooting, stabbing, strangulation, suffocation, poisoning, bombing, fire, drowning, neglect or drug overdose. 

The Radford data again matches Hickey’s exactly in that 34% of partnered offenders used a combination of methods across their series.

The Radford data conflicts with data from Gurian when she states that partnered serial killers use multiple methods 71% of the time. This theory makes sense if you imagine that each offender brings a separate and different weapon than their partner. But thankfully for Tom’s efforts - which you will see why later – partners tend to prefer to utilize a single method 66% of the time. Gurian thought the multiple method theory would hold true for the mixed sex partnerships but the Radford data shows that mixed sex pairs also used one method the majority of the time. 

Gurian was correct in stating that the accomplice is usually a boyfriend or husband when women commit homicide with a male accomplice as the Radford data shows that 66% of female offenders choose a significant other as an accomplice. White states that 24% of men murdered with a family member and 41% with a friend but the Radford data shows a slight divergence in 37 and 35% respectively. White states that 14% of women killed with a family member, 50% with significant other and 5% with a friend but the Radford data show another divergence in 32, 66 and 2% respectively. 

Hickey stated that team offenders were highly likely to come into contact with one another as a result of prior incarcerations and criminal records but according to the Radford data, that holds true for only 7% of the partners. The majority knew each other due to their relationship as family members (37%) or friends (30%). 

Motive is another area where the data differs. Gurian, Fox and Levin note that mixed sex partnered serial murderers killed with pleasure-oriented motivations often for the thrill of the event. With 56% of mixed sex pairings having financial motives and 23% killing for enjoyment/thrill, the Radford data coincides with Joudis and Hickey who state that money was found to be commonly cited as a motive for murder as businesslike ventures were formed for goal driven financial gain.
One lingering question is whether or not the addition of a second party extends or limits the length of an offenders kill span. Hickey notes that killing with a partner greatly increases the likelihood that a mistake will occur and lead to the partner’s identification. 

Hickey and Gurian were correct in stating that partnered serial killers operate in a shorter period of time and are more likely to commit their murders within a single year. A staggering 71% of paired offenders commit their murders in a year or less. 

The rate of killing variable is calculated by dividing the number of victims by the length of the offender's kill span. The higher the number, the more victims the offender killed within a short amount of time. Here you can see that the majority of offenders fall within the less than or equal to 1.00 range meaning that partnered offenders are more likely to kill fewer victims over their careers.
You can also see under the Days Between Final and Arrest variable that the majority of offenders were killing up until they were captured. 

Another area where the Radford database was helpful was in examining the location of events. Jenkins and Gurian state that co-offending pairs are more likely to operate in the west at 43%. According to the Radford data, instances of partnered serial homicide are heavily concentrated in the south at 41% with only 18% of cases occurring in the west. Gurian and Hickey found that 18 – 20 % of offenders operate in more than one state but the Radford data places that number at 26% which is the addition of the offenders killing regionally and nationally. Gurian was accurate in the assessment that mixed sex pairing commit their crimes locally as the Radford data state that occurs 55% of the time.

So before we finish with the data heavy portion of my half of the presentation, lets take a look at what the average serial killer team looks like.

The average killer in a pair was in their late twenties when they began and ended their series and had a 6 year age gap between their partner. They killed five middle aged victims over 500 days. They were generally at large for two and half months between their final murder and when they were arrested. The peak of these types of killings was the late 1980s.
Now I would like to discuss some narratives to put the data into perspective. What I found was that male serial murderers seem to have a knack for finding each other that almost mimics their ability to identify vulnerable victims.

Steven Lorenzo, a serial rapist of gay men, teamed up with Scott Schweickert who he met online to fulfill a fantasy of torturing and killing men. Lorenzo and Schweickert killed two of the nine men they drugged at bars and sexually tortured at Lorenzo’s home. Both men dismembered one victim and scattered the pieces throughout Tampa. The second victim was wrapped in a bedsheet and left in his own vehicle. Schweickert's voluntary confession led police to a cache of nearly half a million images on Lorenzo's computer and blood under the floor of Lorenzo's garage.
Eddie Mitchell and Cortez B. Eagle shot one victim after he had won money in a card game and a second in a home invasion. Both murders were committed in the process of taking items from the victims. 

Leonardo Franqui and Pablo San Martin robbed a bank and murdered a security guard during the robbery. They then ambushed a delivery man and killed him in his vehicle. Both confessed to their crimes when apprehended. 

24-year-old Billy Richardson and 31-year-old Jerard Garrett set up one of their victims for a robbery during a drug transaction in a parking lot. Richardson lured him to the lot while Garrett shot him to death. Six days later, they murdered another man in his home. Garrett had an extensive criminal history and was out of jail on bond during the second killing.

Wesley Shermantine and Loren Herzog grew up as inseparable childhood friends but are now dubbed the Speed Freak Killers due to their methamphetamine abuse and use of the drug to lure victims to their deaths. Together the pair murdered anywhere from twenty to seventy two men and women while killing for sport or trading drugs for sex. Shermantine once bragged to his sister about how he and Herzog had hunted everything they could including the quote ultimate kill but has since backed off that claim, stating that Herzog committed all of the murders as he trained a killing apprentice as means of entrance into the Hells Angels. Herzog blames Shermantine for masterminding the murders stating that he was a nonparticipating bystander that helped cover his dominant and evil friend's tracks afterward. Herzog thought that by cooperating with police that he would be helping to get a killer off of the streets.

Cevelino Capiua changed from a churchgoing, serious student to a man obsessed with obtaining street credibility. He sought guidance from Shawn Womack and became entangled in three murders as his friends noticed drastic changes in his personality like questioning God, doing drugs and partying all the time. Womack gladly took Capiua under his wing, taught him slang words and brought him to an adult bookstore where they killed two men, fifteen days apart. After an arrest for a botched robbery, Capuia confessed that he killed two men with the help of Womack. Womack then confessed that he shot and killed Capuia’s girlfriend. Capuia, who once said that he sees good in Womack, broke down in tears in police custody upon hearing the news.

Dale Hausner and Sam Dieteman partnered to kill eight pedestrians over 16 months in a series of random drive-by shootings. They can be heard over a police wire-tap of their apartment joking about the victim’s pleas, looking at news clippings and arguing with news casters that were providing the wrong information about the murders. The friendship between the two men deteriorated after their capture with Dieteman confessing to two murders and testifying against Hausner. Dieteman stated that he was doped up on methamphetamine and Jack Daniels around the time of the shootings. Hausner blames the murders on Dieteman and Hausner’s roommate.

Ricky Gray and Ray Dandridge were a brutal pairing in that they murdered seven people over a seven-day period after invading their victim’s homes, binding them with electrical cords and using multiple methods such as shooting, beating, stabbing, hanging and suffocation to murder them. Selecting victims was a matter of opportunity like spotting an open door while looking for a house to burglarize. They also instituted ruses like pretending to ask for directions or asking to use a phone. They each helped the other kill a significant other, Gray his wife and Dandridge his girlfriend even though she helped with one murder by posing as a victim allowing Gray and Dandridge to rob her parents. Dandridge confessed to the killings and to burning the victim’s houses and elaborated on their roles in which they traded off who would kill the victims and who would search the house for items to steal.

I wanted to briefly discuss my colleagues’ exposure to the Shermantine and Herzog case. Jeff Rinek’s role in the Shermantine and Herzog case was to obtain the whereabouts of victim’s remains. In his discussions with Shermantine, it was revealed that one reason why he chose to speak was that his former partner will no longer speak to him. During their conversations, Jeff got the feeling that Shermantine was jealous of a victim for being sexual with Herzog.

Gurian offered the theory that shared psychotic disorders could explain the draw that some partners have to one another. Jenkins disagrees stating that mentally unstable individuals cannot attract colleagues to their schemes. The Radford database seems to confirm that latter point as it does not contain any sets of offenders with shared psychotic disorder.
As we will see in the next slide, killers Gordon and Cano were also described by the lead detective of acting like a real couple.

To get some additional insight on Steven Gordon and Franc Cano, I contacted the leader of the team that apprehended the men, Detective Julissa Trapp. Detective Trapp writes that Gordon and Cano did everything together and that they care for each other deeply.

Convicted child molesters Gordon and Cano allegedly prowled the streets of Santa Ana and Anaheim looking for prostitutes and murdered five of them in the Santa Ana and Anaheim CA area over a five month period. The two were best friends and Cano would sometimes stay with Gordon in his RV. The Gordon and Cano case is one of the most detailed views into the decision making process between two murderers that I have run across. It is evident that each thoroughly respected one another and tried to protect each other as the 45 year old Gordon left 27 year old Cano's involvement out of his account. After Gordon thought that Cano did not want to speak with him any longer, Gordon conceded that both suspects picked up prostitutes and killed them, calling Cano an exuberant, active, aggressive participant in the killings. Gordon stated that he picked up the women in his car while Cano hid in the back seat and overpowered them when they got in. As you will see on the next slide, the men exchanged a long series of text messages that show they were debating whether to kill their victims and were hesitant with what to do at some points. 

The women were chosen randomly but there were subtle reasons as to why they were killed. Gordon claims that each time he just wanted to have sex with the women but that things got out of control and the killings were crimes of passion. The first victim was killed because her street name was the same as Gordon’s daughter and that hearing the name "triggered him." When one victim noticed Gordon's electronic anklet, he got angry. Gordon placed the blame on one victim, calling her crazy for pulling on the car's steering wheel. One was targeted because she gave them the finger. One was killed because Gordon apologized and Cano stomped on her neck. Another was murdered after Gordon asked her to make love to him like he was her boyfriend, stay with him and quit the life of working the streets. Cano grabbed her, and she maced them. Gordon proceeded to punch her, as Cano was strangling her.

This case also calls into question the theory that the older offender is supremely dominate while the younger is submissive. Here we see the older Gordon apologizing to a victim while the younger Cano asserting dominance by stomping on her neck. Gordon did not want to kill one victim because she was beautiful, but Cano reminded Gordon that if he didn't, he would have to find a way to remove their DNA from her body. Cano made the decision to pick up at least one of the victims against Gordon wishes. The younger Cano is described as strangling the women while Gordon punched them in the stomach "to get the air out faster." You can see from the text messages that Cano wrote “I thought the next one, you were going to go at it,” “Either Kitty walks or goes to sleep.” Kitty being code for the victim. Gordon did not want to kill her stating "I can't hurt this cat. I just can't," but eventually acquiesced and said “Bye-bye, Kitty,” at 12:13 a.m. “Kitty goes to sleep.” It was the younger Cano that instructed Gordon to “get rid of her” at 11:55 PM and to use Happy Hand, a phrase prosecutors interpreted to mean strangling. Cano resisted Gordon’s requests to do the deed saying that he had a curfew and a parole agent monitoring him – and it was Gordon’s turn.
Although they were cognizant of countermeasures in washing victims and throwing away their belongings elsewhere in another city, they seemed to not care about being linked to the crimes via their sex offender GPS tracking device monitors or cell phone records as Cano constantly texted Gordon, which led investigators to not only suspect the pair worked together. The GPS data matched the place and date of disappearance for at least three of the women. 

Although this case saw the convergence of old-fashioned detective work and high-tech data gathering, there were still some missteps. Despite being registered sex offenders, neither had DNA in any law enforcement database. Gordon and Cano were under the supervision of federal probation and state parole officials throughout the period that prosecutors say they killed the four women. Sex offenders are normally prohibited from associating, but interviews and records have shown the men were close friends.

Here we can see a record of text messages sent between Gordon and Cano that Detective Trapp references in her email. 

It has been said that mixed teams follow conventional sexual stereotypes with a dominating male that bullies or dupes the female into participating. Some, like Jenkins, reject the notion that female offenders are victims coerced into crime and instead view them as active participants, just as capable and complicit as men. Jenkins notes that the victim defense is a byproduct of courtroom strategies meant to portray the woman as being less culpable. Gurian (2013) notes that men are portrayed to be endowed with extraordinary skills of control and influence while women are compliant, feeble-minded and vulnerable, too intelligent to serve as proper victims but weak enough to be manipulated. Many believe that if a female displays masculine forms of aggression, it would require a kind of permission from her male partner. Fox believes that female serial murderers occasionally team up with men often for the thrill of it and participate in order to please their mate but some develop their own satisfaction. It is often assumed that the male is the major culprit while the women killed to preserve the relationship or out of reasons of survival. Gurian (2013) takes it a step further and posits that sexual arousal for some women is dependent on her partner committing a crime. She states that people with a strong predisposition for stimulation-seeking behavior (SSB) would be expected to form couples. She asks if working with a male partner allows them to expand their murder pattern through inclusion of additional motives/victims/methods. White’s data demonstrate that women serial killers killing with a partner were more likely to have been sexually abused in childhood, have psychiatrically disturbed parents, be sexually deviant and to set some victims free. Gurian points out additional characteristics as insecurity, low self-esteem, social isolation and poor education. 

Lovers James Daveggio and Michelle Michaud in the top left corner lured a student into a van rigged with ropes and hooks where they sexually tortured and strangled her. Michaud described each vicious assault as an 'adventure' while Daveggio referred to them as 'hunting.' Michaud stated that the day after Thanksgiving was the biggest shopping day of the year and would be the best day to go kill somebody. Daveggio's daughter testified that her father had been reading books about serial killers. In the top Right corner we see Eric Mickelson and Beverly Arthur. Mickelson may have confessed to the murder of an 87 year-old man but he states that his girlfriend manipulated him into killing him while he was in a "cocaine-induced- stooper" to prevent the victim from turning her in for stealing money to feed their drug habits. Mickelson then said he would take all of the blame if Arthur goes free but his defense team tried to direct all guilt at her even though Mickelson confessed to his mother "I took a man apart. They wouldn't have put him back together unless I put the pieces in their hand. I didn't have to do that. I could have left him out there.“ Below them we have Michelle and David Knotek who killed four people they invited to stay at their farmhouse over a period of fifteen years until their daughters told police they had subjected their victims to painful, humiliating abuse and disposed of the bodies of people down on their luck that they befriended. David was well liked in the community but Michelle was described as having a temper and being evil, volatile, temperamental and an oddball. Richard Davis and Dena Riley in the lower lefthand corner were once known as the FBI’s most-wanted couple for two videotaped rape/torture murders that took place in April and May 2006. Both victims were killed because they knew where Davis and Riley lived and they feared they would contact police about what they had done to them. Samantha Bachynski said that her fiancé Patrick Selepak instructed her to participate in the killings and she complied because she loved him and would do anything for him because he made her feel like a terrific person. Bachynski filled syringes with a mixture of bleach and water and injected it into one victim and pulled on a belt placed around the neck of another while Selepak placed a plastic bag over the victim’s head. Later Bachynski claims that she feared Selepak and helped in the murders because he pointed a gun at her. Selepak has tried to minimize Bachynski's participation and has refused to implicate her. Bachynski stated that she would never have become a killer without the influence of Selepak. Lastly, John Hughes and his girlfriend Dana Tutor killed two truck drivers days apart from one another. The couple used the weapon stolen from the first victim after stabbing him to shoot the second during a botched robbery. Tutor lured the second victim into a rest-stop bathroom and Hughes ambushed him, using the victim’s car to drive to another state after the killing. 

Here we see 52 year old Richard Beasley and his accomplice, 16 year old Brogan Rafferty. As seen in 7% of partnered cases, there was a vast age gap between them, twice the amount of Gordon and Cano. Vast differences in age can sometimes bolster the connection between two individuals as one undertakes the role of teacher or protector while the other assumes the role of student.

Rafferty was primed to bond with Richard Beasley, a man he described as an uncle to him, a relationship that came about due to his absentee, violent and drugged out parents. Rafferty stated that Beasley looked like Santa Claus and was his father without anger, a calm, rational man who offered spiritual or worldly advice and kept candy in his pocket. Rafferty began his relationship with Beasley by accompanying him to church at the age of 8. Beasley would be a normal presence in the Rafferty house for the next 8 years. Beasley became the one person that Rafferty could go to for anything, a father that he never had and an escape because Beasley represented a newer and more appealing vision: expressive, loving, always around to listen and give advice. It was easy for Beasley to be a hero to Rafferty. He did what their distracted, overworked, and somewhat traumatized parents couldn’t do and really connect to Rafferty. 

By his account, Rafferty wanted desperately to see the murders coming and stop them but he was mentally unfit, estranged from society, drunk all the time and thought he was going insane. He sat in the dark most nights after school and could not connect with anyone. He was living moment to moment and contemplated suicide often so that he could join his grandmother in death and says that he was a shell of what he once was. Life revolved around going to meet Beasley, and the time in between. The older Beasley believed in a strict sense of loyalty and if he called Rafferty, he was supposed to come running. Rafferty believes that his early adherence to this code is why he was selected for Beasley’s campaign. But Rafferty was conflicted and struggled with his involvement in the murders from the beginning, even planning on killing his partner, stating that he had turned evil. Those plans never came to fruition due to Beasley’s threats to kill his mother and sister if he stepped out of line. Rafferty was also apprehensive since he though his old friend was still inside Beasley somewhere. Rafferty resolved to let the campaign resolve itself, convinced that Beasley would kill him when they were done and began to dream of an unmarked grave as an end to the “horror story”. In the end, they were apprehended. 

This case is interesting because it highlights the isolation and vulnerability of so many working-class men, who have been pushed into unemployment by the faltering economy. Rafferty believes that Beasley disguised his desire to kill for killings sake by adding a robbery and identity theft angle to his crimes. The state presented a case that Beasley posed as a man named Jack in craigslist ads offering a caretaker job at a nonexistent farm in the hopes of identifying men on the margins that had possessions worth killing for: a truck or a TV or a computer or even a motorcycle. Beasley carefully crafted his ad to stress that those selected for the job needed to start immediately and should bring everything they own with them as they would be living rent free at the farm. Over many drafts, Beasley refined his pitch to the prospective victims to appeal to desperate, working class men by settling on the phrase “idyllic rural job of a lifetime”. Based on his responses to the over 100 replies he received it is clear that Beasley also knew who to avoid. One candidate was soon to be married and another used to be a security guard and was an expert in martial arts.

Beasley portrayed himself to be a helpful gentlemen but he was known in some circles as someone who always had a scam going. He was actually on the run from the law due to his involvement as a pimp doing anything in his power to keep girls at his halfway house including doping them with drugs. Since Beasley was desperate to not end up back in jail, he told Rafferty that he needed his help to survive by obtaining a new identity. After killing his first victim, Beasley dyed his hair brown and found a room to rent. He was adept at keeping police away for a while by tossing one victims items out of their car after he got away because of a jammed gun. He once put a $20 bill under a rock after Rafferty dug a grave for a prospective victim thinking that if it was gone when they came back, he’d know someone had been there. Police eventually identified footage of Beasley from one of his interview meetings while cyber-crimes specialists traced his IP address to a small house in Akron. The owner did not know of a Beasley or Jack because Beasley was posing as his victim. Over time, Beasley began viewing people as the sum total of their possessions, telling Rafferty that he thought one victim could net $30,000 enough for him to make it through the winter. But Rafferty told a story about a victim that was selected because of the promise of goods but was eventually killed for only the five dollars in his pocket and nothing more.

Beasley was very similar to the men he was hunting, himself divorced, and living apart from his child, and was only sporadically employed. And like them, he too had created an intense surrogate family relationship with Rafferty. Beasley created in Rafferty an improvised attachment to a family bond but it was formed under duress and needed to be constantly tended to and reinforced. For men who are failing the traditional tests of marriage and parenting, this kind of intense emotional connection “is the last form of identity available.” Judge Lynne Callahan told Rafferty that he had been “dealt a lousy hand in life” but that he had “embraced the evil,” by digging the graves.
Many regard the Beltway sniper attacks as spree killings given the small timeframe between murders but few are aware that 42 years old John Allen Muhammad and 17 year old Lee Boyd Malvo murdered seven people over ten months in a series of robberies beginning in February 2002 in the states of Alabama, Arizona, Florida, Georgia, Louisiana, Texas, and Washington before the ten fatal shootings in Maryland, Virginia, and Washington, D.C. It was through these test run attacks that the partners procured the laptop used to plan many of the Beltway sniper attacks and sealed their demise by leaving a fingerprint later used to tie them to the attacks after Malvo called to taunt the police about this unsolved homicide in Montgomery, Alabama. Their more coordinated Beltway sniper attacks began and ended in October 2002 and saw the partners switch from a .22-caliber pistol to a Bushmaster rifle and use the rolling sniper's nest in the trunk of the Chevrolet Caprice. Muhammad and Malvo increased the frequency of their attacks with six fatal shooting deaths in the first 15 hours. On another day, four people were shot dead within a span of approximately two hours but once they started covering a wider area two or three days fell between shootings due to due to heavy traffic and the lack of a clear shot or getaway at locations. Victims were shot performing everyday activities: mowing grass, pumping gasoline, changing tires, walking, or reading on a bench. Authorities discovered a four-page letter from the shooter in the woods that demanded $10 million, threats to children and a Death Tarot card with the statement Call me God" on the front. A series of trial exhibits suggested Malvo and Muhammad were motivated by an affinity for Islamist Jihad but investigators eliminated terrorist ties or political ideologies as a motive. Instead, Muhammad intended to kill his second ex-wife with the other shootings intended to cover up the motive for the crime, since Muhammad believed that the police would not focus on an estranged ex-husband as a suspect if she looked like a random victim of a serial killer. 

After undergoing extensive psychological counseling, Malvo admitted to the 17 murders after being freed of Muhammad’s brainwashing. He stated that he was sexually abused by his former mentor, “taken under his wing” as a teenager and taught about the Nation of Islam. Muhammad allowed Malvo to move in with him when he was 15 and put him on a one meal a day diet of soy burgers and soup coupled with vitamins and exercise. Malvo was complicit in the attacks as they handed off driving and shooting duties to each other and was allowed to weigh in on locations, even disagreeing with some due to level of witnesses and surveillance cameras. Malvo claimed that he was the sole shooter in order to protect Muhammad from a potential death sentence but now realizes that Muhammad “made him a monster”. One victim that survived received a letter of apology from Malvo. 

According to Malvo, Muhammad's multiphase plan consisted of meticulously planning and mapping the area to formulate a predetermined path of escape after killing six white people a day for 30 days. They would then kill a cop and blow up his funeral to kill the attendees. The final phase was to kidnap children for the purpose of extorting millions of dollars from the government so that they could set up a camp to train children how to terrorize cities. They would recruit impressionable young boys with no parents or guidance from YMCAs and orphanages. As he did with Malvo, Muhammad would act as their father figure and train the boys in weapons and stealth. After their training was complete they would be sent them out across the United States to carry out mass shootings in many other cities to send the country into chaos.

Brothers have been known to team up from time to time. The most infamous recent case, whose three year anniversary is in 8 days, being 26-year-old Tamerlan and 19-year-old Dzhokhar Tsarnaev the “Boston Marathon Bombers”. I include them here since they are suspected of a mass homicide in Waltham, MA on September 11, 2011 and because they were planning to detonate explosives in Times Square after the Boston Marathon. Fun fact - The actors that will play them in the upcoming Patriots Day movie have just been cast. 

Tyrone and Jerone Sotolongo, in the top right hand images, were arrested under suspicion of committing three murders, one for a victim’s gold chain. 

19-year-old Robert Bever and 17-year-old Michael Bever detailed to officers a gruesome plot to carry out further killings. Robert expressed a desire for notoriety for being a serial killer telling of a plan to head west in the family SUV armed with guns, ammunition and makeshift bombs to randomly attack other locations and kill 10 people at each place after having killed their family, cutting up the bodies, and storing them in bins in the attic. Detectives said they wanted a Wikipedia page and media coverage.

Nowadays, connections between people are hard enough to maintain, but these co-offending murderers somehow find and support one another through the repetitive trials of victim identification, murder and body disposal. Perhaps these shared experiences bolster the respect each has for the other and make their bond impenetrable in their minds. After all, each has something to lose in a relationship build on mutually assured destruction. 

19-year-old Jake England confessed to shooting three people and 32-year-old Alvin Watts confessed to shooting two. All the victims of the shooting spree were black and police have said one motive for the shootings may have been England's desire to avenge his father's fatal shooting by a black man two years ago.

Here you can see some exchanges between England and Watts on Facebook where Watts attempts to console the frequently sullen England. 

78 year old Helen Golay and 75 year old Olga Rutterschmidt murdered two vagrants in 1999 and 2005 staging each to look like hit and run incidents in order to collect on multimillion-dollar life insurance policies they had taken out on the men. Before their arrests Golay and Rutterschmidt collected over 2 million dollars in proceeds from the policies. Evidence was raised at trial of their intent to victimize a third man but he escaped their grasp after growing suspicious of their intentions. In secretly recorded tapes the younger Rutterschmidt could be heard telling Golay that she was stupid for taking out the extra policies and that the total blame would lay at her feet. The two were described as meeting by chance and having an arm's-length friendship built around "harvesting" the down and out for quick cash due to failed marriages and shaky finances. Both told stories of painful childhoods and a bond that grew during the spandex-era fitness craze that peaked in the 1980s as they trolled for marks careless with their money and taken in by their looks. Detectives stated that their scheme fell apart because they grew to distrust each other. 

Ex-Russian surgeon Dmitriy Yakovlev and his wife Julie were a husband-and-wife identity theft team suspected of killing retired NYPD mechanic Michael Klein (left), Russian translator Irina Malezhik (center) and jewelry importer Viktor Alekseyev, whose dismembered body was found a year earlier in New Jersey woods. The Yakovlev’s were found guilty of bank and credit card fraud charges in connection with the stealing of their victims' identities.

Using a 9mm handgun, revolver and shotgun, 31 year old Jerad and 22 year old Amanda Miller shot to death two Las Vegas police officers and an intervening armed civilian at separate locations in June 2014. They pinned a note on one officer’s body, which read: "This is the beginning of the revolution." The Millers had planned to "take over a courthouse and execute public officials" as their ideology has been described as "along the lines of militia and white supremacists”. Jerad had a history of run-ins with the law beginning in 2001 and an online presence over the last year that included dozens of Facebook posts like the one you see here and 20 YouTube videos posted under the username USATruePatriot. Posts almost always contained conspiracy theories and anti-government rhetoric to the tune of stopping oppression with bloodshed and a coming sacrifice. He expressed strong hatred for law enforcement, gun control and surveillance. Jerad met and married Amanda in 2011 and like Jerad, she had a Facebook account, in which she made multiple posts, including numerous photos depicting the Millers dressed as supervillains. In one of the photos you see here, they were dressed up as Batman villains Harley Quinn and the Joker. In one of her Facebook posts, which was dated May 23, 2011, she warned us all that we are lucky she cannot kill us yet but that she would one day. Together the Millers supported the Patriot movement, a collection of various groups with a shared ideology for limited federal government but there is no evidence that they belonged in a specific group. Friends of the Millers reported that they idolized the two perpetrators of the Columbine High School massacre, and wanted to follow in their footsteps.

31 year old David Pedersen and his 24 year old girlfriend Holly Grigsby killed Pedersen’s father because he molested two young relatives and his wife because she knew about it and didn't stop him. Pedersen’s neck tattoo invokes "Supreme White Power," and those beliefs led them to kill a man in Oregon they thought was Jewish, and another man in California who was black. In trying to protect his girlfriend, Pedersen takes "full responsibility" for the crimes but Grigsby admitted to killing Pedersen’s stepmother by stabbing her. What is astonishing is that Grigsby gave up a life with her husband, child and skipped her parole check-ins to be with Pedersen. Her facebook page stated that she was devoted to her family and following the path of God. They were headed to Sacramento to "kill more Jews" when California Highway Patrol officers caught up to them.

In late 2015, an American-born U.S. citizen named Syed Farook and his Pakistani-born wife Tashfeen Malik killed 14 people with semi-automatic pistols and two .223-caliber rifles at a Department of Public Health training event and holiday party using ski masks and black tactical gear. Pipe bombs were meant to target the emergency personnel but failed to detonate. The shooters reportedly spent at least a year preparing for the attack, including taking target practice and making plans with Farook's mother to take care of their child. Federal prosecutors allege that in 2011, Farook and Marquez conspired to carry out shooting and bombing attacks but they abandoned those plans at the time. The large stockpile of weapons used by the shooters and an examination of digital equipment recovered from their home led investigators to believe that they were in the final planning stages of future attacks. The FBI stated that the married couple met online and were "homegrown violent extremists" inspired by foreign terrorist groups but were not directed by such groups and were not part of any terrorist cell or network, much like the Millers on the previously slide. The FBI's investigation had revealed that Farook and Malik were "consuming poison on the Internet" and both had become radicalized "before they started dating each other online" and "before the emergence of ISIL."

I have included the San Bernardino killers in this presentation because evidence points to their plans to commit additional murders by bombing a California college and killing Los Angeles commuters. Over the Atypical Homicide Research Group’s email listserv, two experts debate whether or not they began killing due to the influence of forces other than their own abnormal psychology. Many would classify their actions as an act of terrorism but since we use a liberal definition with the database, Malik and Farook would have fit within the rolls of multiple murder if they had successfully carried out another attack at a separate location. 

The Radford data shows that 71% of partners confessed their crimes and implicated their partner.
Eric and Kim Williams engaged in a campaign of revenge by shooting to death two victims that had prosecuted Eric for burglary and theft while he was in office as Justice of the Peace. These events became known as the Kaufman County murders with the first being described as an ambush in a parking lot and the other a home invasion type assault. Like some of these investigations, the possibility that the murders were committed by larger groups was considered, in this case the Aryan Brotherhood but Eric’s desire to show off by sending a tip into Kaufman County Crime Stoppers that was traced back to his computer resulted in their apprehension. After the murders, Kim sought a divorce from Eric and testified against him.

Cousins Caroline Peoples and Angel Wright-Ford used friendship and sex as strategies to lure people who they then shot and robbed. They were skilled at duping victims into positions of weakness even stripping naked with one victim before shooting him in the head and stealing his DVD player, jacket, cell phone and car. Ford had previous contact with two of the victims, one as a nurse’s assistant and the other from a romantic relationship. As Ford distracted the men, Peoples shot them on separate occasions. Ford then encouraged another man to enter their van with the promise of sex but Peoples was waiting in the back with a gun. The women took 200 dollars from his body before they dumped it in the parking lot of a bowling alley. They were about to pose as prostitutes to lure another man but Peoples called her friend and took her to a restaurant. This murder was significant for the partnership as they both took turns shooting the victim. Once they were captured, they each confessed and implicated the other. 

A chance meeting at a party brought together two future murderers, a partnership described as a perfect storm of deviancy. Konrad Schafer was 15 when he was charged with the murders of David Guerrero and Eric Roopnarine in 2013. Schafer fatally shot 17-year-old Guerrero, who was on his way to catch the bus for work, because he thought it would be fun to kill. Days later, Schafer and David Damus forced their way into the home of Roopnarine, a 22-year-old club promoter, because they wanted the 20,000 dollars he had bragged of having. Damus shot him as he begged for his life while Schafer stabbed him in the neck. The deaths took place during a 15-day spree of 22 shootings in Osceola County during the summer of 2013. The shootings left bullet holes in homes and cars. Schafer’s father purchased the weapon due to his son’s claims of being bullied at school and in his neighborhood. Damus’ change in personality came from too much partying while Schafer’s was a byproduct of his leukemia medication. The two were caught after bragging about living the “savage life” to friends. Schafer confessed through tears within minutes of being arrested.

Vigilante killer William Inmon wanted to rid society of what he considered to be less-than-desirable people including a drug-using Vietnam vet, a sex offender and a teenager struggling to kick a drug habit. Inmon killed one victim because he claimed he touched him and others inappropriately, another because he supposedly shot Inmon’s dog and mistreated people. According to detectives, Inmon was genuinely remorseful about his third killing in which he was goaded into the murder by the father of the victim’s girlfriend. Police focused their attention on the group of youths that discovered one of the bodies before Inmon confessed to the murders. 

When asked whether he had any regrets, Inmon said he wished he had not involved others in the murders. What will remain a mystery is if Inmon is truly remorseful or if he blames his accomplice Joseph Roberts for contributing to his capture.

Prosecutors say Stephen and Linda Schneider ran a "pill mill," carelessly writing prescriptions for potent, addictive painkillers to people with severe pain but also to drug abusers who feigned symptoms. The government accused Schneider of being little more than a drug dealer who did not carefully monitor cases, prescribed excessive dosages and wrote prescriptions so freely he became known among some patients as the "Candy Man.“ Schneider and his wife were convicted of a moneymaking conspiracy prosecutors say was linked to 68 overdose deaths. They were directly charged in 21 of the deaths.

The 2-year-old son of Herbert and Catherine Schaible died of untreated pneumonia in 2009 after which they promised a judge they would not let another sick child go without medical care. But now the faith healers have lost an 8-month-old to what a prosecutor called "eerily similar" circumstances. Their pastor has said the Schaibles lost their sons because of a "spiritual lack" in their lives and insisted they would not seek medical care even if another child appeared near death.
What is open for debate is whether or not they are serial killers. We would consider them to be and placed them under the neglect category of the database.

Perhaps the greatest exploration of what it means to be in a partnership was demonstrated fictionally through the relationship between Hannibal Lecter and Will Graham over three seasons on NBC beginning in 2013. Building on statements made by former profilers that to catch a monster you need to become one, the series sees Hannibal try to convince Will to release the monster that is building within him. In the series finally, Hannibal’s goading culminates in the murder of a serial killer at the hands of both Hannibal and Will Graham as they team up to take him down. Will then plunges the two over a cliff after realizing what they had become together. 

This telling varies greatly from the Thomas Harris books and I thought it was worth mentioning here because of the way that the series creator chose to portray the recruitment of Will into Hannibal’s plans, the lengths Hannibal went to to ensure his success and that it took three years to culminate this way.

The best outcome of forming the collaborative mentioned earlier was the capture of suspected serial murderer Felix Vail who possibly worked with a partner, David Thomason, during at least one of the murders. My exposure to Vail began in October 2012 when Northeastern University’s Jack Levin connected me with investigative reporter Jerry Mitchell in an effort to locate Jim Bell, a former Major Case Specialist (MCS) with the Federal Bureau of Investigation (FBI). Bell investigated Vail as a serial killer suspect briefly in 1993 before retiring from the Violent Criminal Apprehension Program (ViCAP). Gregory M. Cooper, a member of the Collaborative, supervised Bell and suggested contacting the FBI. 

Major Case Specialist Wayne Koka liaised between Acting FBI Behavioral Analysis Unit-4 Unit Chief Armin Showalter, Jerry and myself. Coupling Jerry’s extensive exposé on Vail with my knowledge of serial killers, they were convinced of Vail’s potential. By January, Showalter had spoken with Detective Randy Curtis of Calcasieu Parish Sheriff's Office who summarily reopened the Mary Horton Vail cold case. Koka later modestly labeled their assistance as “routine”, but we understood it to be a vital intervention. 

Since Jerry suspected Vail of the 1973 and 1984 disappearances of his longtime girlfriend Sharon Hensley and wife, Annette Craver Vail, we continued to delve into his past. We consulted with Dr. Henry Lee about DNA evidence, contacted Thomas A. DiBiase and the folks at NamUs about other no-body murder prosecutions, reached out to a jewelry expert to identify earrings that Vail retained, and emailed the Internet Adult Film Database to inquire about a triple X film in which Vail may have participated. 

I learned about Vail’s outlook on life from a series of audio recordings that a private investigator supplied to us. The tapes revealed a man that strove to maintain a standard of living that was untethered to obligations who wanted his life to be unaffected by the turmoil caused by lesser people. Vail is a self-proclaimed detached observer whose limiting factor was his need to consume his partner’s resources and move on once they were gone. This worldview contributed to his aspiration to escape the commitment of becoming a second-time father, allegedly resulting in the murder of his wife, Mary Horton Vail.

Vail refers to himself as a scientist studying the anatomy of the ego. To him, the ego is an entity whose mission is to overtake our electrical life force, or spirit, which he labels as the limiting factor of the human species. Vail hoped to triumph over the ego and reach a state of “free brain awareness” where total autonomy, self-governance and spiritual enlightenment can be attained. Suppression of the ego requires fasting and the “ceasing of verbalization” where all toxins can be purged and unwanted aspects abandoned.

Vail is handicapped by a preference for abstract thought, an immensely inflated sense of self-worth and a tendency towards megalomania. His desire to tap into the consciousness of strangers to access information within their minds signifies Vail’s lifelong quest for absolute omniscience. Vail takes pride in thinking “outside the social parameters” to which he states others are programmed. Ignoring “social ethics” and “religious morality” affords Vail the ability to care not for what is deemed permissible by society and disregard the illegality of his prior actions. Growing up on a farm with sharecroppers and orderlies instilled in him a penchant for dehumanization and the opinion that some are subhuman. As no woman could equal him emotionally, mentally, or spiritually, they existed merely to be used. To avoid sending “red flags”, he pretends to be influenced by the disapproval of others. Vail faces a trial date of August 8th.

Here are the articles that I referenced throughout the presentation.

DeLisi (2013) Do Gang Members Commit Abnormal Homicide? American Journal of Criminal Justice
Gurian (2011) Female Serial Murderers. International Journal of Offender Therapy and Comparative Criminology 55(1)
Gurian (2013) Explanations of mixed-sex partnered homicide. Aggression and Violent Behavior
Gurian (2015) Reframing Serial Murder Within Empirical Research: Offending and Adjudication Patterns of Male, Female, and Partnered Serial Killers. International Journal of Offender Therapy and Comparative Criminology
Fox/Levin (2015) Extreme Killing
Hickey (2013) Serial Murderers and Their Victims
Jenkins (1990) Sharing Murder: Understanding Group Serial Homicide. Journal of Crime and Justice 13 (2)
Jones (2008) Partners in crime: A study of the relationship between female offenders and their co-defendants. Criminology & Criminal Justice 8 (2)
Juodis, M., Woodworth, M., Porter, S., and Brinke, L.T. (2009). Partners in Crime: A Comparison of Individual and Multi-perpetrator Homicides. Criminal Justice and Behavior. 36:824-839.

White (2014) Twice the Evil: A Comparison of Serial Killers who Killed with a Partner and Those 
Who Killed Alone. American Journal of Forensic Psychology. 32 (1)

Friday, May 1, 2015

Addressing the Challenges and Limitations of Utilizing Data to Measure Serial Homicide

The following was presented to the Homicide Research Working Group on June 11, 2015:

Enzo Yaksic a and Michael Aamodt b

a Serial Homicide Expertise and Information Sharing Collaborative. Boston, MA

b Department of Psychology, Radford University. Radford, VA


According to Beasley (2004), the study of serial murder should be objective, standardized and include as many subjects as possible. Although researchers have been collecting serial homicide data for decades, it was done disparately. Hinch and Hepburn (1998) categorize past attempts as “dealing with narrowly defined acts and the most sensational cases.” Lack of reliable data has contributed to the slowing of research on serial crime (Petee and Jarvis, 2000) and is identified as a key obstacle for the future (Dowden, 2005). Leyton (1996) and Skrapec (2001) have advised scholars to abandon egos, academic ‘turf wars’, and self-serving agendas in search of a greater understanding of the phenomenon. In an update on the ‘Evolution of Serial Murder as a Social Phenomenon in American Society’, Hickey (2014) acutely summarizes the plight endured by those delving into this work, acknowledging that “being a researcher in this area has required getting past misinformation and sensationalism, finding others who share similar research interests, and dredging up reliable data.”

Overcoming these barriers is an ongoing endeavor, undertaken by the efforts of those involved in the Serial Homicide Expertise and Information Sharing Collaborative (SHEISC), a network of one-hundred academic and law enforcement professionals with the goal of coming to a greater understanding of the serial murderer (Boyne, 2014). In 2015, after a combined total of thirty-seven years amassing data on serial homicide offenders, Michael Aamodt and Enzo Yaksic began recruiting scientists to analyze the output in unique ways. Relationships were built with Clare Allely, author of Neurodevelopmental and Psychosocial Risk Factors in Serial Killers and Mass Murderers (2014), Ronald Hinch, author of Researching Serial Murder: Methodological and Definitional Problems (1998), authors Mikhail Simkin and Vwani Roychowdhury of Stochastic Modeling of a Serial Killer (2014), Marissa Harrison, author of Female Serial Killers in the US: Means, Motives, and Makings and Virginia Beard, author of Death-Related Crime: Applying Bryant's Conceptual Paradigm of Thanatological Crime to Serial Homicide. To encourage further empirical studies, Aamodt and Yaksic provided an opportunity to bolster future work in this arena and increase sample sizes by supplying each with the entire Radford/FGCU-SHEISC Serial Killer Database (Aamodt, 2014). 

In the past, serial homicide databases were sparsely populated as academicians collecting information made it available only to their own research team (Ramsland, 2010). To protect self-interests, most operated in ‘information silos’, hoarding data and secreting source material. Procurement of these files now comes at exorbitant financial cost (Canter, 2011; Godwin, 2012) as records were often kept in paper format (Egger, 2014; Geberth, 2010) or within now defunct or corrupted computer systems (Waters, 2013). As a result, some materials no longer exist (Leyton, 2013). Byproducts of these actions led to the creation of different definitions, the use of assorted sources, the surveillance of non-comparative variables and the inability to validate information.

The variance of emphasis on the nuances of serial murder has led to the use of multiple definitions (Morton and McNamara, 2005) as criminologists have historically been restrictive in their interpretations of what constitutes a serial murderer (Ostrosky-Solis et al., 2008). Wright et al. (2009) state that much of the scholarly research has been hindered by the definition of each type of killer, differing on requirements such as the number of murders, the types of motivations and the temporal aspect (Morton and Hilts, 2008). Starting from a more inclusive definition may hold advantages, according to Osborne and Salfati (2015), but, by excluding certain types of killers, analysts have reduced the pool of research subjects (Cluff et al., 1997). The Radford/FGCU-SHEISC Serial Killer Database (Aamodt, 2014) employs the broad two victim definition provided by the Federal Bureau of Investigation (FBI) as it encompasses the full array of serial murderers by not referencing underlying motivation, behavior or psychological characteristics (Brantley and Kosky, 2005; Hargrove, 2010). Radford data include financial, professional contract, revenge, gang, organized crime, robbery/homicide and witness elimination offenders among the more ‘traditional’ serial sexual murderers. Research efforts have been damaged in recent years due to a hyperfocus on the serial sexual killer as the terms sexual homicide and serial murder have become synonymous (Petee and Jarvis, 2000).

Criminologists protest the inclusion of gang and professional murderers in serial offender databases since they occur alongside functional (Ferguson et al., 2003) violence and have rational motives (Jenkins, 2002). This viewpoint reinforces that offenders must utilize violence unconventionally to qualify as a serial murderer. Many, including the killers themselves (Valencia et al., 2013), believe that self-motivated serial murderers do not belong juxtaposed to ‘hitmen’ since they are paid to kill and do not choose their own targets (Hickey, 2013). Conversely, these murderers display the intent to kill anyone, at any time (Vronsky, 2013) and are seemingly gratified by appeasing their greed. Lester and White (2014), as well as agents of the FBI (Morton and McNamara, 2005), acknowledged that organized crime, contract and drug/gang killings are serial murders that can be motivated by revenge, loyalty or profit.

Evident is the risk of diluting a sample and compromising the integrity of data by conflating various types of multiple murderers together (Giannangelo, 2013). However, excluding killers that cross between subcategories hinders the advancement of serial homicide research (Clemente, 2013). Hickey (2015) notes that broad definitions may not be meaningful, but excluding financial motives and those who kill acquaintances is based on speculation rather than on any empirical foundation. Aamodt and Yaksic’s application of the Modified Delphi Technique (Custer et al., 1999) on an instituted panel of experts demonstrate a wide range of opinions on the topic (Aamodt and Yaksic, 2015a). Although these disagreements highlight the difficulty of maintaining collaborative relationships, the group posited that the broad categorical term “Multiple Event Murderer” could be used as a means to study the multitude of subsets of offenders either together or separately, defined henceforth as: Any person(s) that cause(s) the death of another through illegal means more than once in at least two locations. 

The benefit of cataloging multiple murderers using one overarching classification scheme is that it allows individual researchers to adapt as needed and avoid the shortfalls of the existing definitions (Adjorlolo and Chan, 2014). Rather than engaging in the process of retrofitting offenders into categories to suit specific study parameters, whole subsets of offenders can be included or excluded from analysis, depending on the author’s pre-defined criteria. The detriment of this approach arises when psychologically dissimilar populations are compared between studies (Aamodt and Yaksic, 2015a). Researchers must be cognizant that serial murderers cannot be fit into one single behavioral profile (Hickey, 2015) and, based upon the uniqueness and variances of human behavior, be aware of the limitations in typing the serial murderer (Morton and McNamara, 2005).

Fox, Levin (2011) and Yaksic’s meticulous tracking of adjudicated serial murder series over several decades revealed that the phenomenon is in decline (Beam, 2011). Yaksic’s (2013a) reasoning behind the decrease was initially met with trepidation but several of the proposed theses have since been accepted (Fox and Levin, 2014; Hickey, 2015) as probable explanations for the downward trend. It is presumed that advances in technology have made it easier for law enforcement to consider that a serial murderer may be operating in their area (Kaste, 2015). Jurisdictional conflicts have subsided in favor of increased collaboration with the FBI and surrounding departments while the public is consulted for assistance (Backus, 2015a) more frequently. Cell phones, always connected social media accounts and the dawn of the surveillance age add other measures of risk to an offender’s decision to victimize others. The Internet provides would-be offenders the opportunity to placate themselves without exploiting unwilling participants. Greater utilization of the underground sex trade and the likelihood of offenders warehousing abductees contributes to a decreased need to eliminate complaining witnesses with such regularity. Efforts to educate the public about these offenders led to increased awareness that odd behaviors, stalking offenses, paraphilias and violent tendencies toward animals or others in youth are part of a larger group of warning signs. A greater distrust of strangers led to the abolishment of hitchhiking and parents reluctant to allow children to play freely without supervision (Aamodt and Surrette, 2013), diminishing potential victim pools. Harsher punishments and less use of parole ensures that would-be serial murderers are incarcerated for longer. Serial murder is not viewed as the shortcut to celebrity status it once was since news coverage of these events has lessened over the years. Many would-be serial murderers are captured after their first murder due to incompetence, before they have the opportunity to amass larger victim counts (Aamodt and Yaksic, 2015b). Future generations may witness an even greater decrease in victimization as long haul truckers are replaced by automated vehicles (Davies, 2015). The decline in serial homicide calls into question the image of the infallible, successful killer these offenders were once thought to be. Societies’ past ignorance of their means and motives allowed serial murderers freedoms they can no longer enjoy. While the desire to become a serial murderer has not dissipated among offenders (Aamodt and Yaksic, 2015b), these factors may have permanently displaced some offenders, forced others into altering their modus operandi or into early retirement.

Still others may have begun adopting tactics commonly associated with the spree murderer (Aamodt and Yaksic, 2015b). Long after Muhammad and Malvo (Koerner, 2002), the debate about how to typify spree murderers continues due to those that carry out their crimes in ‘spree-like’ frequency but, as agents of the FBI have stated (Morton and Hilts, 2008), the motives and tactics of a serial murderer (Earl, 2013). Researchers have been reluctant to juxtapose these offenders or admit witnessing the convergence of the spree and serial murderer in recent years. It is disputable that spree and serial murderers should continue to be stratified separately since the ‘cooling off period’, used to make distinctions between potentially similar serial offenders, is now characterized as a historical artifact (Douglas et al., 2013). Osborn and Salfati (2015) concluded that spree and serial homicide may not be distinguishable, including in their data eight instances of one day time intervals and one series that lasted only three days.

Nearly a decade ago, Salfati et al. (2006) concluded the only study comparing serial and spree murderers, finding that spree offenders were generally 29 years old, killed on average six victims with firearms, most often in one day at anywhere from two to six locations. Seventy-three percent of these perpetrators were killed before capture. Aamodt and Yaksic (2015b) found that spree offenders in their data were also typically 29 years old, but killed on average three victims with firearms most often over a one week period at three locations. The majority of offenders in the Aamodt and Yaksic (2015b) inquiry were arrested rather than being killed in police shootouts after embarking on a suicide mission. Although spree offenders did share similarities with serial murderers, it is not yet known which psychological traits are mutual or if patterns in precipitating factors can be established. Aamodt and Yaksic (2015b) concur with Salfati et al. (2006) that more data is needed to determine if spree and serial murderers should continue to be stratified separately.

After incorporating spree murderers and instances of urban violence into their serial homicide dataset, Hickey (2015) and Yaksic found evidence of a change in victimization rates. Fewer cases of only female victims are co-occurring with an increase in males being targeted. Fewer strangers and more family members are killed with a slight drop in the number of prostitutes being singled out. There are fewer numbers of victims per offender and fewer cases involving more than one state. Fewer cases of strangulation are recorded alongside more cases involving shooting as the sole method of killing.

Still, Homant and Kennedy (2014) stipulate that a serial murderer’s subsequent killings should be part of a separate sequence of behaviors. Those committed by spree murderers are said to be part of one continuous event, often the byproduct of situational violence (Daniels, 2015). Not only is the sequence distinction less useful if these offenders are viewed as Multiple-Event Murderers (Aamodt and Yaksic, 2015a), but serial murderers can and have been fueled by similar precipitating incidents.

Although Beasley (2004) noted feelings of restlessness and impulsivity among serial murderers, they have been characterized as cold and calculating methodical planners that commit unprovoked, patterned and predatory sexual attacks on strangers. Spree killers are typed as temperamental, impulsive and bombastic with initial murders being haphazard retaliatory reactions directed at acquaintances (Salfati, 2006) whose subsequent murders often help them obtain necessities (Daniels, 2015). Perhaps, however, there are circumstances and environmental factors that may preclude multiple murderers from acting in the manner that they would ideally choose. Some offenders are given the luxury of time between offenses, not because of superior knowledge, talent or skill, but due to variables beyond their control including the degree of witness involvement, varying levels of police pressure and even luck. If a spree-type offender eludes police, they may bide their time, reenter society, and possibly continue killing again in the future, unabated. Similarly, serial murderers can exhibit ‘run and gun’ behaviors by the end of their series (Smith, 2009; Sparacello, 2011). By ignoring the stratification question, researchers overlook the evolving nature of serial homicide and disregard how serial murderers are molded by social conditions, cultural changes and external pressures (Warf and Wardell, 2002).

Early qualitative research efforts were ambitiously spearheaded by agents of the FBI who conferenced with twenty-five serial murderers in the early 1980s in an attempt to understand the circumstances behind their existence by immersing themselves in their life histories (Ressler and Burgess, 1985; Beasley, 2004). Since then, researchers have instituted lore by either intentionally or unwittingly overemphasizing anecdotes gathered from these interviews. Stereotypes emerged over the past forty years, forming due to the scarcity of systematic studies (Arndt et al., 2004; Jenkins, 1994), the desire to monetize the concept and the tendency for some to consciously invest in catering to those that actively embrace the more gruesome aspects of serial murderers and their deeds (Yaksic, 2014a). As such, researchers have spent the greater part of the last decade combating antiquated viewpoints and dismantling myths from past eras (Fox and Levin, 1999; Sterbenz, 2015; Yaksic, 2013b). Consequently, there were very few comparative studies, virtually no biopsychosocial studies, an absence of more sophisticated statistical analysis and a repetitive use of small, nonrandom samples using retrospective data at the beginning of the millennium (Meloy, 2000). Dowden (2005) suggests that researchers refocus their efforts as inquiries made by those working outside the field of serial homicide research are often the most potent. 

Serial murder has been transformed into a profitable construct, often exploited to satisfy our curiosity (McNamara and Morton, 2004; Beasley 2004). Falsehoods are often promulgated by unqualified individuals, self-ascribed forensic criminologists, due to the ease with which information can now be generated and disseminated for financial incentives (Yaksic, 2014a). There are those that imprudently wield criminal profiling as a weapon in a game of good versus evil where the good guys battle and triumph over the bad guys (Mains, 2015a). This infantile worldview may produce good entertainment (Mains, 2015b) but also inevitably induces a false sense of knowing these offenders. As such, serial murderers have been portrayed as prolific evil geniuses, inhuman psychopathic monsters and dysfunctional white male loners, unusual in appearance and incapable of maintaining long term relationships. They are called cunning predators that ceaselessly hunt dozens of strangers to fulfill a desire for bloodlust. They supposedly possess the ability to not only evade the police but expertly engage them through the media and frequent their hangouts to learn about cases, all while yearning to be caught.

Leading research shows that serial murderers do not consistently behave this way (Fox and Levin, 1999; Hickey, 2015). The current authors have each separately imparted their findings on the issue of race and the serial murderer. Yaksic (2006) contentiously stated that every other serial killer since 1995 has been African American. Others (Hickey, 2015) have since validated this proposal, finding that it has held true almost a decade after being posited. Aamodt (2008) found that the commonly held demographic profile correctly matches only eighteen percent of serial murderers. As Beasley (2004) notes, the prevailing thought that serial murderers sadistically kill for sexual gratification, engage in animal torture, are physically or sexually abused as children, become more evidence conscious over time and allow media coverage to alter their criminal intentions must be challenged. Results from Bateman and Salfati (2007) indicate that serial murderers are not consistently performing the same crime scene behaviors throughout their series. Coupled with the findings of Schlesinger et al. (2010), these revelations test the notions that serial murderers consistently take souvenirs or leave signatures, escalate in their violence as they continue killing, improve their methods and change their strategies over their careers. Violent acts performed on a body also should not automatically signal the presence of a serial murderer.

Serial murder is thought to be an affliction that overtakes an offender’s life but they are not hostages to this cycle; they can control their desire to kill. Offenders are not always in prison, the military, at college, or in a mental health facility during time intervals (Morton et al., 2015) and rarely begin to unravel at the end of their series. Many have criminal records that reflect histories mired in anti-social behavior but some do display remorse (Yaksic, 2012) and can be affected by what they do (Levin and Fox, 2008), sometimes coping with their actions by abusing substances. Murders can be committed serially due to subtle factors such as the offender’s perception that a victim lied, cheated, insulted, or hurried them (Quinet, 2011). Victims are often selected not as substitution for someone they know but based on availability, vulnerability, and desirability (Morton et al., 2015). It is also obsolete to classify serial murderers as either organized or disorganized as this investigational dichotomy has not been used in practice during much of the past decade (Morton et al., 2015).

Abiding by tropes can influence the course of serial homicide investigations. A private investigator from Sarasota, Florida used only the physical attributes of eighteen potential victims to connect the disappearances simply because they “look just like sisters”, drawing a comparison to the archaic archetype of Ted Bundy (Gleiter, 2014). Although firearms are the highest proportion of kill method in the Radford data (Aamodt, 2014), an investigator characterized a recently apprehended serial murderer’s use of a firearm in each of four homicides as “rare” (Alexander, 2014). Most still consider as fact the old adage that serial murderers desire a ‘hands-on’ kill and must strangle their victims to feel the life leave their bodies.

To avoid further pitfalls, Beasley (2004) recommends supplementing interviews, like those conducted by Pino (2005) and Reavis (2011), with information from large scale databases in order to obtain a more informed view of the serial murderer. ‘Big Data’ provides many benefits to almost all sectors of society (Davenport, TH., and Dyché, J., 2013; Venton, 2015) but has yet to be utilized to effect this microcosm of the criminal justice system. While researchers have now officially convened in an effort to attain this aim (Boyne, 2014), several limitations have been encountered.

All facets of serial homicide research are fraught with quantification issues due to the use of outmoded data collection methods. No official mechanism exists for capturing instances of serial homicide as the FBI’s Uniform Crime Report (UCR) and Supplementary Homicide Report (SHR) lack a specific entry field. Researchers inclined to count the frequency of events and make determinations about their instance in society cannot track serial homicide easily as there is a great amount of disagreement as to what exactly constitutes a serial murder series. Categorization efforts have been ongoing since the inception of this phenomenon but researchers are no closer to consensus (Ostrosky-Solis et al., 2008) on classification today than they were forty years ago. Attempting to include motive into the definition of serial murder results in some degree of subjectivity (Ferguson et al., 2003) as it must be inferred from observable behavior (Kraemer et al., 2004) and depends on history, context and expectation; constructs that are not only impossible to quantify but unique to each individual. The news media oftentimes does a poor job of accurately labeling a serial offender based on motive, as evident in the recent trials of Aaron Hernandez (Jones, 2014) and Dzhokhar Tsarnaev (Zalkind, 2014). Those regularly deemed spree killers can also erroneously be given the serial killer designation (Winton et al., 2014). For these reasons, the addition of serial homicide offender records to databases can be an unnecessarily subjective process.

The emotional ‘cooling off period’ is a confounding concept that has been used to differentiate between multiple murderers. While experts disagree on a standard ‘cooling off’ length, many continue to utilize this temporal element as part of their exclusion criteria. Osborne and Salfati (2015) note that there is a lack of research to develop an understanding of ‘cooling off’ and that it should be discarded and re-conceptualized into time intervals. Since these intervals could be less than one day, the continued use of the temporal distinction has restricted the utility of the current serial murder definition (Adjorlolo and Chan, 2014). Although serial murderers may return to their usual way of life in the time breaks between homicides, researchers have little understanding of the behaviors that they partake in during these interruptions. It is impossible to discern the degree to which serial murderers remain entrenched in their killing lifestyle. While it may appear that they are taking care of their children or going to the store, they may actually be dedicating effort to planning future crimes, ruminating about past ones or managing the impression made on others (Levin and Fox, 2008). An offender’s dormant period is thought to be psychologically beneficial to them but implies that they engage in violence as part of a stress-relief regimen to resolve a buildup of internal conflict (Corzine, 2014). This viewpoint wrongfully insinuates that serial murder is driven only by aggression and agitation and that offenders work themselves into a frenzy, or ‘heat up’ before each kill (McClellan, 2014). This outlook, as well as the use of the word ‘emotional’ to describe this period (Aamodt and Yaksic 2015b), conflicts with the perspective that serial murder is a predatory crime whose offenders are well-controlled, cold and calculating (Myers, 2014).

Unlike in other fields of inquiry, attempts to collect primary source information are hampered by extraneous factors. Researchers must contend with limited access to subjects due to their incarceration, death or refusal to participate in research studies. When access to subjects is granted, offenders often alter their version of events to better suit their needs or cannot accurately recall how events transpired. Although some serial murderers are consumed by their killing lifestyle (Fox and Levin, 2011), most often lack enough insight into themselves to provide useful and actionable information. Since opportunities for interviews are sparse, statements given by murderers are overblown, generalized and given more weight than they deserve. Building rapport with a subject can be a time consuming process, often lasting months or even years. Regardless, primary source interviews (Pino, 2005; Reavis, 2011) should supplement the information culled from secondary sources so that offenders’ actions are not minimized after being reduced to mere data points in an Excel worksheet. Sorting offenders by only demographic variables can lead to a loss of narrative components and an overreliance on selected anecdata. 

Available data can also be rather difficult to aggregate and collate. Titlow (2014) cataloged some of the hardships the current authors encountered during the process of data transformation while merging each of the databases received through the SHEISC initiative. Although a more real-time, ‘root cause analysis’ of offenders’ methods and motivations would greatly enhance law enforcement’s response to these matters, gathering primary source information on each of the 3,949 serial homicide offenders listed in the Radford/FGCU-SHEISC Serial Killer Database (Aamodt, 2014) would take more than a lifetime, even if they were universally available. While potentially able to amass far larger victim counts than their American counterparts, international killers are woefully understudied due to substandard record keeping and unestablished judicial systems in foreign countries as well as cultures that do not obsess about the criminal mind.

Linking and attributing homicides to one killer can be a challenging process, spanning many years and encompassing the efforts of hundreds of individuals (LePard, 2015; Lohr, 2015). Taskforces are charged with identifying the perpetrator after a large expanse of time since the initial murder occurred (Backus, 2015b). The length of legal proceedings contributes to the dearth of primary source research materials, such as an offender’s journal, as these items are warehoused in evidence lockers and not revealed until a trial (Zapotosky, 2015). As is the case with serial murder suspects Lonnie Franklin (Gerber, 2015) and Felix Vail (Yaksic, 2014b), bringing offenders to trial can take half a decade. Due to the threat of lawsuits from individuals that are wrongly labeled with the ‘serial killer’ tag, researchers often wait until their conviction to add them to datasets. This artificial lag greatly diminishes an offender’s impact on the data because researchers customarily generate statistical output based on the data that becomes available during the new edition cycle of their academic textbooks. Excluded from analysis would be those offenders discovered during the resolution of a cold case (Hoffer, 2015), for example, since they occurred outside of the parameters of the author’s timeframe. The drawback of such a stringent focus on cases surrounding the textbook’s publication period is the inability to conduct any type of systematic comparison of offenders from previous eras to these more recent killers.

Complicating matters are those individuals that have no involvement in a series of murders but claim responsibility for them and those that boast about murders beyond the scope of their series. Each scenario makes adjudicating these crimes difficult. Still, others refuse to accept responsibility for the totality of the killings they did cause. Some individuals listed in The Innocence Project (Scheck and Neufeld, 2015) and The National Registry of Exonerations (2015) were released after the true perpetrator was revealed to be a serial murderer (Coker, 2015). Over the years, a few series were even determined to likely be nonexistent – the Smiley Face killings of college aged men in the Midwest and Northeast (Drake et al., 2010), the canal ‘Pusher’ case in Manchester, England (Slater, 2015) and the Phantom of Heilbronn, supposedly operating in Austria, France and Germany from 1993 to 2009 ().

Due to Institutional Review Board restrictions and confidentiality agreements (Salfati, 2011), the most detailed records of the crime, those of law enforcement, usually are not available to researchers (Kraemer et al., 2004). Also routinely out of reach is comprehensive documentation related to a case, including investigative, autopsy, forensic and evidence analysis reports; crime scene and autopsy photographs, diagrams, sketches, and maps; victimology information; offender background; and any confessions or admissions by the offender (Beasley, 2004). Even if available, these documents cannot account for missed offenses that the offender committed that are unknown to police (Osborne and Salfati, 2015). Information gleaned from law enforcement sources is also processed through several layers of individuals before it ends up as a data point in a database and is therefore exposed to all the biases and distortions that accompany human interpretation of facts. These records can contain misinformation as investigators’ levels of experience with and understanding of such offenses may vary widely (Morton and McNamara, 2005), leading them to only record information fitting their notions of what will be important for the investigation (Bateman and Salfati, 2007). An unavoidable limitation of all serial homicide datasets is that what is not known about victims cannot be known (Quinet, 2011) as they are the primary, and perhaps the sole, witness. Due to the outcome of the crime, he or she is no longer able to provide the necessary evidence (Bateman and Salfati, 2007). 

Because of these reasons, most researchers are forced to collect information from secondary sources, such as true crime books and news media reports (Morton and McNamara, 2005). Reliance on this approach is problematic because the veracity of claims made in true crime books are often unverifiable and reports often contain varying degrees of information pertinent to investigating this phenomenon (Morton and McNamara, 2005), which oftentimes contributes to missing data (Bateman and Salfati, 2007). For example, universally incorporating offenders that commit two homicides is arduous since news outlets infrequently refer to these offenders as serial murderers. Instead, these offenders are muddled with double-murderers (Hoffer, 2015), killers whose two homicides occur in the same incident, at the same time. This oversight has led to several records being overlooked during searches.

Estimating the true prevalence of serial homicide is complicated by the complex nature of the data. Due to the serial murder entertainment industry, superfluous content often overtakes search results during research, leading to an oversampling of the most bizarre cases, at the expense of more mundane and more common offenders (Beasley, 2004). Researchers do not factor unsolved homicides into their analysis since these victims cannot be definitely attributed to the actions of serial murderers. Also, as unapprehended serial murderers are probably hidden within the nations numerous DNA backlogs (Nelson, 2010), some researchers deem it unethical to produce a number that would adequately capture the serial murderer’s occurrence in society. It is also impossible to know the identities of burgeoning serial murderers. Those that maintain the intent to commit a subsequent offense after being apprehended for their first homicide are not included in the data as no academic study has been dedicated to this offender population. The instance of false positives, those that express the desire to kill serially but are not responsible for any homicides, is unknown.

An interdisciplinary team of researchers, journalists and data scientists have been assembled in an effort to address the limitations outlined in this report (Boyne, 2014). To overcome these barriers, we must begin to adapt processes proven useful in other industries. Virtual breakthrough series collaboratives (Zubkoff, 2014), encouraging the free exchange of ideas and network building, inspired the creation of the SHEISC in 2010 which resulted in the capture of serial murder suspect Felix Vail (Yaksic, 2014b). IBM’s Watson supercomputer is primed for use in the criminal justice system (Wyllie, 2011) but its potential impact on serial homicide research and investigations is unknown at this time.

Digital information dashboards, data displays and electronic surveillance tools are used in healthcare systems to track performance on key indicators, allowing for ‘drill down’ capabilities to reveal information hidden amongst lower level data (Chen et al., 2014). These displays would serve the criminal justice system by subsuming data from various sources into one location to provide a semi real-time overview of probable serial murder activity while compiling data for scientists to analyze.

After completing work applying an algorithm on unsolved homicide cases using the statistical technique of cluster analysis (Hargrove et al., 2011), Thomas Hargrove founded the Murder Accountability Project (Hargrove, 2015) to ensure that police increase their reporting of homicide occurrences to the FBI using the UCR and SHR mechanisms. Dallas Drake of the Center for Homicide Research has begun work on the Wyoming Homicide Database Project (Drake, 2015), a pilot to test the feasibility of obtaining information on solved homicides directly from law enforcement institutions. Data scientist Peter Brendt is at work applying natural language processing techniques to large swaths of data in an effort to generate a type of ‘weather map’ detailing probable serial murder activity among listings of unidentified bodies and missing persons (Brendt, 2015). Aamodt and Yaksic continue to populate the Radford/FGCU-SHEISC Serial Killer Database (Aamodt, 2014) with new cases. Relationships should be fostered with local law enforcement crime analysts and statewide fusion centers under a joint understanding that utilizing data to address this longstanding criminal justice issue is of critical importance. Linking these efforts together under one umbrella may have distinct advantages, as yet both unexplored and unexploited.

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