How to Catch a Serial Killer

A Lear jet“[I]deas about who killed whom does not come to the criminal profiler in flashes of insight, nor does a group of FBI profilers fly around the country in a Lear jet and solve heinous murders within a few days with the help of a computer genius back in Quantico who seemingly has unlimited resources and who admittedly conducts illegal hacking into data banks that are highly confidential.”

This excerpt from a recent Forensic Science International paper (1) pokes fun at criminal profiling as portrayed on television shows such as Criminal Minds. However, this is just another example of Hollywood producers embellishing reality and stretching the truth to try to increase the entertainment value. [To learn about how the television show CSI has warped public perception of the forensic sciences, check out The Reality of Crime Scene Investigation. Part I: Common Myths].

So, if these Criminal Minds and CSI approaches to catching murderers aren’t accurate, how do law enforcement officers identify killers and bring them to justice?

Law enforcement agents have many tools in their tool belts to solve crimes, including fingerprinting, DNA analysis, toxicological assays, ballistics and even criminal profiling. I have written about forensic DNA analysis in past blog entries, so I won’t go into detail about those techniques here. However, I think it is useful to define criminal profiling. Criminal profiling is the examination of physical evidence left at a crime scene to better understand the psychological or behavioral traits of the perpetrator.

In light of current television shows such as Criminal Minds and CSI, you might conclude that forensic analysis and criminal profiling alone are instrumental in focusing law enforcement’s attention on a particular suspect, but is this really true?

In the Forensic Science International paper, John White et al. provided a historical summary of how criminal profiling and forensic techniques have been used to cast suspicion on murder suspects and, after studying 200 serial killers, identified 12 ways that police are alerted to a suspect in a criminal investigation.

The authors’ historical summary dates back to 44BC, when a physician performed what might have been the first medical autopsy to determine which of 23 stab wounds killed Julius Ceasar, and discusses advances in technology such as detection of poisons in human tissue samples, stereoscopic microscopes used by ballistic analysts, fingerprint analysis and the polymerase chain reaction. The authors give examples of criminal profilers, including one of the most astute, but fictitious, criminal profilers—Sherlock Holmes—as well as real-life criminal profilers who studied Adolph Hitler, a child serial killer in Georgia, a prostitute killer in New York, a vampire-like killer in California and an arsonist in New York City.

To answer the question posed above, “How do police identify suspects in a serial killer case?”, they combed newspaper articles, books and other media reports of cases involving serial killers, which they define as a “person who has killed at least three people at different locations with a ‘cooling off’ period between the killings”. They then modified this definition to include killers such as John Wayne Gacy and Jeffrey Dahmer, who abducted their victims from different locations but killed them at the same location, and Angel of Death killers such as Donald Harvey, Teri Rachels and Charles Cullen. They found that serial killers were first put under the police microscope by:

  1. A victim was voluntarily released after the abduction or assault.
  2. The murderer was killed during the crime.
  3. The killer went voluntarily to the police and confessed.
  4. The killer was identified by a witness as being with the victim shortly before the murder.
  5. Communication with the police or media led to the killer’s identification.
  6. The murderer was caught in the act.
  7. A victim survived the attack after being left for dead.
  8. A victim escaped.
  9. The killer was linked to the crime scene.
  10. The murderer was linked to the victim by some means other than an eyewitness.
  11. The killer was arrested for some other offense, then linked to the murders.
  12. The killer was turned in by someone who knew the offender.

A victim was voluntarily released: As you might expect, there don’t seem to be many sympathetic serial killers because only 1% of serial killers were identified after they voluntarily released one of their victims and this victim supplied critical information to law enforcement. This category includes serial killer Bobby Joe Long and Peter Kurten.

The murderer was killed during the crime: This category included only 1.5% of serial killers examined. This category includes Wayne Nance, Joseph Mumfre and Dean Corll.

The killer went voluntarily to the police and confessed: Again, this category of serial killers was sparsely populated, with only four (2%) of the 200 killers feeling pangs of remorse so strong that they made a trip to their local constable. This category includes Edmund Kemper, who was known as the Co-ed Killer in California, and Wayne Ford.

The killer was identified by a witness as being with the victim shortly before the murder: Eyewitness accounts of a killer being seen with a victim shortly before his or her death were responsible for only 2% of captures. This category includes Antone Costa and Wayne Boden.

Communication with the police or media led to the killer’s identification: The undoing of 2.5% of serial killers was their communication with the police or media. This category includes the BTK killer (Dennis Rader), who sent a traceable computer disk to the local media; William Hance, who sent letters written on military stationery from his own military base; and Maury Travis.

The murderer was caught in the act: The serial killers in this category were caught as they were attempting their next attack. Harvey Glatman, Jeanne Weber and Richard Cottingham are among the 11 (5.5%) serial killers in this category.

A victim survived the attack after being left for dead: In 15 (7.5%) cases, a victim was so badly injured or was able to mimic death that the serial killer believed her to be dead, but the victim recovered and pointed the finger at her would-be killer. Included here are Harvey Carignan, who was sentenced to death but was released on a legal technicality, allowing him to continue his killing spree for another 20 years; Richard Tingler, who tried to kill all witnesses in a dairy bar robbery in 1968; and Rudolf Pleil, who raped and murdered at least nine women.

A victim escaped: I had hoped that this number would be higher, but in only 16 cases (8%) the victim was able to escape his or her assailant and make a report to police. This category includes notorious serial killer Jeffrey Dahmer, Tracy Edwards and Gerard Schaefer.

The killer was linked to the crime scene: In 16.5% of the cases, it was an association with the crime scene that led to the serial killer’s capture. For example, Arthur Shawcross was arrested after he returned to revisit his latest victim’s body, which had been discovered but was left undisturbed and was placed under police surveillance. Gary Ridgeway, who was responsible for the Green River killings, and Dennis Nilsen are also in this category.

The murderer was linked to the victim by some means other than an eyewitness: This category includes the 33 (16.5%) serial killers who were identified using information procured through a third party, such as a relative, friend or coworker. John Wayne Gacy’s last victim had told his mother that he was going to visit a local carpenter by the name Gacy before he disappeared, and this information led police to search his home and find the bodies of his other victims. Suspicion was cast on Nannie Doss after her fifth husband’s death, and she eventually confessed to killing 11 family members, including two children, two sisters, her mother, a mother-in-law, a grandson and a nephew. Mary Beth Tinning became a murder suspect when nine of her children died over a 13-year period.

The killer was arrested for some other offense, then linked to the murders: Another 16.5% of serial killers were arrested for some other criminal offense, then confessed or were linked to the murders by police. Infamous killer Ted Bundy, Albert DeSalvo (the Boston Strangler) and Fred West fall into this category.

The killer was turned in by someone who knew the offender: The largest percentage of serial killers (20.5%) were turned into police by someone they knew, such as an accomplice, cellmate, family member or friend. This includes Ted Kacinzsky and Charlie Starkweather.

The end result is that none of the 200 serial killers were identified through forensic evidence alone. The one possible exception was arsonist John Orr, who was not included in this study because he did not fit the authors’ description of a serial killer; he was identified solely based on fingerprints left at the crime scenes. However, the authors note that forensic analyses may prevent someone from becoming a serial killer simply because any killers who leave behind enough physical evidence (e.g., fingerprints or DNA) at the crime scene for forensic analysis are caught before they can commit additional murders.

So, what role do forensic analysis and criminal profiling play in police investigations? Criminal profiling can be useful when narrowing the field of suspects but is of minimal help when trying to identify definitively a perpetrator; in this study, criminal profiling was mentioned as a law enforcement tool in only seven of the 200 cases. Once a suspect is identified by one of the mechanisms listed above, evidence obtained through forensic analyses can be used to elicit a confession or presented in court to gain a conviction (or acquittal). More important than either of these tools in the initial identification of a suspect is the public. In many of these cases, the serial killer was apprehended due to alert members of the public who reported their observations to police.

White, J.H. et al. (2011). The utilization of forensic science and criminal profiling for capturing serial killers. Forensic Science International, 209, 160–5. PMID: 21333473

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Terri Sundquist

Terri has worked as a Scientific Communications Specialist at Promega Corporation for more than 13 years, and prior to that, spent more than 5 years solving problems and answering questions as a Promega Technical Services Scientist. She graduated with B.S. degrees in Chemistry and Biology at the University of Wisconsin—River Falls, then earned her M.S. in Molecular Biology from the Mayo Graduate School in Rochester Minnesota.

One thoughtful comment

  1. Great post Terri, thanks for the twelve point summary of the paper by White et al which I will now also definitely check out. I am a pharmaceutical executive with a background in pharmacogenetics but am also a writer, and my debut (FBI) thriller entitled The Ripper Gene will be coming from Tor-Forge books in 2015. I recently visited the FBI field office in Manhattan with a group of other writers and provided a summary of the tour we received to the rest of the writers in the International Thriller Writer’s (ITW) organization…your post here could serve as an additional critical reference as well since it details how FBI actually ultimately “finds” their serial killers. After their (the FBI’s) openness and willingness to share their daily activities with us as writers, I definitely feel a debt of sorts to imbue my own books with as much realism as possible (while keeping plot moving as is necessary for fiction!). Delicate balancing act but worth it. Thanks again for this informative post and I look forward to reading others.

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