• Killer Data examines the phenomenon of serial murder using data collected from a variety of sources to review offender patterning with a focus on contemporary cases. This type of attention will allow for a broader understanding of modern-day serial murderers and will help to dispel some of the myths that surround offenders.

    The current serial murder classification scheme incorrectly types serial murderers as supremely intelligent killing machines while discounting their socialization, experiences, and choices. This book exposes serial murderers as run-of-the-mill hometown losers, who brutalize women, and are lucky to escape apprehension. Like other atypical homicide offenders, modern-day serial murderers are propelled forward by a deep sense of entitlement, easy access to firearms, and a nonchalant attitude toward using murder to attain their goals. Readers should come away with a deeper understanding not of the ultra-rare or the "deadliest" serial murderers but of the more common offenders who pose a consistent threat to day-to-day life. The book utilizes the Consolidated Serial Homicide Offender Database, one of the largest and most robust open access databases of multiple murders available, presenting new thinking on areas such as:

    • myths and stereotypes

    • the impact of entertainment on the perception of serial murder

    • inaccurate prevalence estimates

    • spree/serial hybrid offenders

    • the classification of two and three victim serial murderers

    • how serial murderers pursue longevity

    • the characteristics of aspiring serial murderers

    • whether hit men and gang members are serial murderers

    • if and why serial murder is in a state of decline

    • how many serial murderers are responsible for the homicides that sent innocent people to prison

    • luck as a factor of “success” for serial murderers.

    These findings are illustrated with 200 narrative vignettes of serial murder series that occurred between 2011 and 2021, such as Itzcoatl Ocampo, Charles Severance, Nikko Jenkins, and Pamela Hupp, offenders who may be unfamiliar to many but represent the next iteration of the serial murderer.

    Correcting decades of flawed assumptions about serial murderers, and written in an accessible and concise style, Killer Data is essential reading for students and scholars of criminal justice and criminology, law enforcement professionals, and the interested general reader.

  • List of Tables

    List of Figures

    Foreword

    Preface

    Acknowledgments

    1: Serial Murder: Then and Now

    Introduction

    A New Criminal Type…or All Concerted Hype?

    Myths and Stereotypes

    Pursuing Fame through Serial Murder

    The Inflated Prevalence of Serial Murder

    Obstacles to Establishing Serial Murder Research as a Legitimate Endeavor

    2: What Do We Know about Serial Murder and How Do We Know It?

    Explanations for Serial Murder

    The Behavioral Science Unit

    Organizing the Study of Serial Murder

    3: Serial Murder: 2011 – 2021

    Overview

    Parameters

    Findings

    How Are Serial Murderers Portrayed across Seminal Studies?

    How Do the Current Review’s Findings Compare to the Seminal Studies?

    4: An Overview of the Modern Serial Murderer

    The Importance of Narrative Context

    Perpetrator Type

    Traditionally Defined Serial Murderers

    Two-Victim Serial Murderers

    Serial-Spree Murderers

    Female Serial Murderers

    Team-Based Serial Murderers

    Multiple-Event Murderers

    Caregivers

    Potential Serial Murderers

    Potential Serial Murderers Who Were Successful

    Serial Shooters

    Survivalists

    Motive

    Anger

    Psychosis

    Ideology -– Extremist Violence and Racial Hatred

    Enjoyment (-– Thrill, Excitement, and Power)

    Financial (-– Criminal Enterprise)

    Professional Contracts

    Drug Trafficking

    Case-Specific Factors

    The Use of Technology

    Refusing to “Age Out” of Crime

    Parolees

    Extensive Criminal Histories

    Warehousing Victim’s Remains

    Victimizing Fellow Inmates

    Military Service

    Victims as Collateral Damage

    “Prolific” Status

    5: Concluding Thoughts

  • I first began multiple homicide investigation and research in 1981 as the Atlanta Child Murders drew national attention. There were a handful of professionals such as Robert Ressler (FBI), Elliott Leyton, Ph.D., Steve Egger, Ph.D., Ronald Holmes, Ph.D., and Kim Rossmo, Ph.D., who also were intrigued by persons capable of orchestrating mass and/or serial murder. At the same time, forensic psychology, a new field of science that was forming, along with the introduction of DNA and advanced criminalistics, and the technology explosion that gave birth to mass and social media, brought increased scrutiny to homicides and other crimes of violence. Like the American gold rush of 1849, academics, professional practitioners, and law enforcement turned their attention to this “emerging social phenomena” of mass and serial murder.

    One of these very astute and dedicated individuals was Enzo Yaksic. I met him several years ago via email. He had been assisting a well-established researcher but expressed interest in my work. Enzo offered his assistance in supporting my on-going research. As we emailed and talked by phone, I found him to be intelligent and genuinely interested in discovering truths about serial murder, a topic smothered in mythology, popular opinion, and error. Of course, intellectual curiosity, like any scientific tool, requires constant examination and questioning. Enzo understood that the questions to be asked were far more important that simply finding answers. Enzo, as it turned out, was not only a data-miner, but he also sought to develop understanding of the dark world of serial murder.

    Over the past several years, Enzo has participated in and been invited to many professional events related to serial murder investigations and research. He has helped organize on-line professional forums, assisted some of the most well-known and respected researchers in the field, and has collaborated and published scholarly articles on serial murder. His penchant for accuracy and detail is impressive. He has earned respect amongst those of us in the scientific community of serial murder research. His new book, Killer Data: Modern Perspectives on Serial Murder, is the culmination of many years of data collection and analysis. Like most social science research, his work is foundational, not definitive. He has parsed serial murder data and has come to some conclusions that will, no doubt, spur other researchers to investigate. This is, indeed, the nature of scientific inquiry and discovery.

    In this timely work, Enzo reviews the origins of the serial murder phenomenon and where we are now in serial murder research. This is followed by expanding our perceptions of serial murder and projecting future research. In his section on Case-Specific Factors, Enzo examines the use of technology in tracking and examining serial murderers. He notes that some offenders refuse to age out and includes insights on certain violent parolees who murder fellow inmates. He broaches the issues in warehousing the remains of serial murderer’s victims and includes an important discussion of military service victims. Each of these topics offers insights and ideas for additional research, data collection, analysis, and publication. To that end, we owe Enzo a debt of gratitude for his collaborative spirit, integrity, and loyalty. May his ongoing data-mining quests for those scholarly gold nuggets benefit us all.

    Onward Enzo!

    Eric W. Hickey, Ph.D.

    Author of Serial Murderers and Their Victims

  • Killer Data arrives 20 years after my first exposure to serial homicide, which occurred in the summer of 2001 when Gary Lee Sampson murdered retiree Philip McCloskey in Marshfield, Massachusetts, college student Jonathan Rizzo in Abington, Massachusetts, and Robert Whitney in Meredith, New Hampshire, over a three3-day period. I was mystified as to how someone could victimize others in that manner, especially those offering aid. Perhaps my proximity to the homicides bolstered my interest. My sheltered life certainly contributed to my astounded confusion. These homicides shattered my belief in a quick and judicious justice system as Sampson could have been apprehended before the murders if not for his call to surrender being disconnected by the FBI. Sampson’s actions also fervently shook away any remnants of a belief that the world was a safe and welcoming place. After his capture, it was revealed that Sampson had apparently suffered some adverse childhood experiences, and I grew curious what exactly separated his experiences from my own.

    I was a psychology student at Northeastern University but was inspired by these events to transfer to their world-renowned criminal justice program. Through my coursework, I learned just how little was known about people like Sampson. Definitional discordance made it difficult to determine even basic facts such as his standing as either a spree killer or a serial murderer. No one knew if there was one factor or many circumstances that transformed Sampson into a killer. There simply was not a large and reliable base of data from which inferences about multiple murderers could be drawn. What was understood about these types of offenders was derived from anecdotal evidence and came from individual case studies conducted by disparate scholars, psychiatrists, true crime authors, and the FBI, each with their own agendas. The FBI’s Criminal Personality Research Project was similar to other efforts of the time in that the small number of subjects and the limited racial makeup of the offender cohort made the generalization of findings controversial.

    Knowing this, and after repeatedly encountering the same offender profiles, I decided to learn from the source. I applied for and obtained an internship at the FBI’s training facility at Quantico, Virginia. It was here that I discovered through an independent data collection effort that half of serial murderers since 1995 had been African American, a finding that directly contested established beliefs. After returning to Northeastern, I continued to develop this spreadsheet of offender data as part of a directed study. Initially a rudimentary effort, this project quickly grew to thousands of names and attracted the attention of others amassing their own information. We soon began to pool our spreadsheets and built a team of like-minded scholars invested in breaking down the barriers to the open exchange of serial homicide data. This network of committed researchers, practitioners, and police personnel faced several obstacles, many of which originated as one-sided motivations on a personal and institutional level. But we carried forth and formed the Atypical Homicide Research Group and succeeded in creating the Consolidated Serial Homicide Offender Database, the first open serial murder database in the world. These resources will prove critical as we begin the arduous process of identifying the next generation of researchers who will carry forward the foundational work of the pioneers who are beginning to retire or pass away.

    Although the research and investigation of serial murder has improved since the early days, the entertainment realm – with output such as Mindhunter, A Killer by Design: Murderers, Mindhunters, and My Quest to Decipher the Criminal Mind, The Killer Next Door, Clarice, and The Little Things – clamours to reset our progress by intentionally transporting viewers back to the 1970s, 1980s and 1990s, the peak of serial murder in the United States. In so doing, we are made to think that these offenders continue to present an unmanageable threat. Without accurate prevalence estimates, some researchers and police officials have taken advantage of a wider societal fear of the serial murderer to scare the public and create a continual need for expert services. Killer Data is an opportunity to quiet the noise surrounding the topic of serial murder, focus attention on modern perspectives of the phenomenon, reignite academic interest, and highlight recent research in the area. Readers of Killer Data may be frustrated to find that more questions are raised than are answered. Some might think that there are too many numbers while others may demand even more. But until we determine how serial murderers have adapted to the modern world and agree on who has the expertise necessary to properly interrogate the phenomenon, there will always be confusion surrounding what it will look like and what our collective response should be in the coming years.

    There is much more work to be done so let us get to it.

  • Like many things in life, Killer Data would not have come to fruition without the guidance and mentorship of several individuals. To get to this stage of my career as a serial homicide researcher and stay the course, I have relied on a great deal of patience, perseverance, luck, and good timing when facing a variety of odds. Please allow me to thank those that helped me get to where I am today.

    Academic giant Dr. Jack Levin was an eccentric and defining figure in my life during my time at Northeastern University. As an early pioneer of serial murder research, Jack normalized academic interest in what can be viewed by outsiders as a strange area of study. Without Jack, I may have dedicated my efforts elsewhere. It was through Jack that I was able to help resolve the homicide series of Felix Vail and I am grateful for that experience.

    Retired FBI Special Agent Vickie Woosley’s support of my early aspirations in serial homicide research, coupled with her institutional contacts, allowed me to make inroads with leading scholars and set me up for long-term success. The lessons in decency, patience, and fortitude that Vickie taught me have never left me and have proven useful every day since. I have been able to approach many adverse situations due to the lessons I learned while under Vickie’s mentorship. Knowing Vickie changed my life in countless ways, and I cannot be more grateful.

    Dr. Eric Hickey’s contributions to the field of serial murder research and investigation are legion. As one of the first to statistically analyze serial murder, Eric set the precedent for the rest of us. Eric displayed immense courage and fortitude to stay the course professionally as others sought fame and fortune on the backs of victims during the heyday of serial murder. By not following the crowd, Eric was able to gain insight into the criminal workings of serial murderers that others overlooked. Eric’s support of the next generation of researchers makes him the most forward-thinking person in the field today. I looked to Eric when thinking about how best to navigate the obstacles in the way of a long-standing career. Without Eric elevating my work, I may have grown weary and petered out long ago. I cannot hope to repay Eric for the valuable life lessons and the innumerable hours he has dedicated to our work. I can only hope to have a tenth of the impact on serial homicide research that Eric has had.

    The foresight shown by retired journalist Thomas Hargrove in the formation of the Murder Accountability Project and his leadership since its founding have been inspirational. Tom’s dedication to the victims of homicide has been infectious. Many thanks to Tom for those early foundational conversations all those years ago. It is important work. While we do not always agree on the prevalence of the phenomenon, I respect the search for answers. What a journey it has been.

    The late Dr. Leonard Morgenbesser was among the first to see the merit of forming the Atypical Homicide Research Group (AHRG) and gave an early iteration of this think tank a chance by providing institutional support. Thank you for your foresight, Leonard. Rest in peace, old friend. Thanks go to the late Robert Keppel for being the first to reject my invitation. You made me work harder to refine our mission statement and purpose. Rest in peace, Bob.

    To all the members of the AHRG and the early contributors to the Consolidated Serial Homicide Offender Database (Eric Hickey, Ronald Hinch, Brigadier Gérard Labuschagne, Janet McClellan, Bryan Nelson, Michael Newton, Kenna Quinet, Cloyd Steiger, and John White): history will look favorably on you for your belief in open access to information. Rivalries and turf wars have no place among scholars. Your support of these networked activities should be widely commended. It is critical that we remember that siloed thinking led to the creation and subsistence of serial murder myths and stereotypes for decades.

    Many thanks to Evelin Csabai for your research assistance. This work is better off for your involvement. To my buddy, Clare Allely, thank you for keeping me on track and talking me off the ledge during this process. I dare say I would not have finished this book if not for your support. Thank you to Routledge editor Lydia de Cruz who had the foresight to see that the field needed a new perspective on serial murder and approached me to provide it. Lydia was a strong ally who was patient and kind when I needed it throughout the publishing process. Thanks to my family for providing the resources and support necessary to begin my foray into higher learning.

    Lastly, I would like to thank my wife, Rose, for never judging or condemning my pursuit of answers in this area of research no matter how much time it has taken away from our lives. Your insight on how to navigate the various personalities associated with this area of research has been heeded on more occasions than I wish were necessary, but it has always been on point. Thank you for your encouragement and for being my travel buddy when in- person conferences were the norm. I could not have done it without you, Rose!

  • “As a researcher of serial murder, I am all too familiar that many hyped publications and other media offer no citations of source material for their information and claims about those who commit these heinous crimes. In the book Killer Data: Modern Perspectives on Serial Murder, prolific researcher and gifted author Enzo Yaksic brings us on a fascinating empirical exploration of this phenomenon. While acknowledging that we are just beginning to understand some of the factors that motivate predatorial perpetrators of serial homicide, Yaksic takes us on a scientifically informed journey through killer facts and theories. He introduces us to the scientific study of serial homicide, reviews and compares historical and contemporary research, and provides new, fascinating data about modern incarnations of these murderers. This book is a must-have foundational guide for any researcher or student of serial homicide, and it will appeal to members of the public interested in these criminals and crimes that fascinate us and fuel our nightmares.”

    —Dr. Marissa A. Harrison, Penn State Harrisburg, Research Psychologist and Author of Just as Deadly: The Psychology of Female Serial Killers (forthcoming, Cambridge University Press)

    “Killer Data provides a contemporary exploration and insight into serial murder. A must-read contribution to the field!”

    —Dr. Clare Allely, University of Salford, England, Reader in Forensic Psychology and author of The Psychology of Extreme Violence: A Case Study Approach to Serial Homicide, Mass Shooting, School Shooting and Lone-actor Terrorism

    “Enzo Yaksic has been immersed in serial murder research for nearly two decades, amassing information about deviants and psychopaths to better understand them. The culmination of that effort is Killer Data, a definitive state-of-the-union report on serial killers in the 21st century. Through his research and insights into the continually changing and evolving phenomenon of serial homicide, Yaksic ushers students, scholars, police officials, and the news media into a new unprecedented understanding of serial killers today and potentially in the near future.”

    —Dr. Peter Vronksy, Ryerson University, lecturer and author of Sons of Cain: A History of Serial Killers From the Stone Age to the Present (2018), and American Serial Killers: The Epidemic Years 1950-2000

  • Enzo Yaksic has studied serial murder for 20 years and is the director of the Atypical Homicide Research Group (AHRG), a think tank that strives to understand the modern-day multiple homicide offender through the systematic collection and analysis of data. The AHRG organizes and maintains the Consolidated Serial Homicide Offender Database, the largest open repository for information on atypical homicide offenders. As the author of 15 manuscripts on serial homicide, Enzo is at the forefront of serial murder research. Enzo’s current work with the Murder Accountability Project aims to educate Americans on the importance of accurately accounting for unresolved homicides within the USA by using the Supplementary Homicide Report to help uncover suspicious clusters of potential serial homicide activity. Enzo has been quoted in the Los Angeles Times, The Washington Post, The New Yorker, and USA Today. Enzo was profiled in a Boston Magazine article titled Profiler 2.0.