The Bundy Effect and the Study of Facial Features in Victims
The benefits of biometrics for serial killer investigations may be overstated.
Posted April 24, 2026 | Reviewed by Lybi Ma
I’ve recently seen some headlines that tout a biometric method for linking a serial killer’s victims. The Daily Mail , for example, exclaimed, “The Ted Bundy Effect: Study Confirms Serial Killers Attack Victims Who Resemble Their Mums.” Yet the article refers to only Ted Bundy and Ed Kemper as examples. That’s insufficient, not to mention unrepresentative. I looked for more support.
The reporter describes a team from Murdoch University in Australia that has developed a “forensic intelligence tool” to analyze facial measurements for accurate comparisons. The lead researcher, Professor Brendan Chapman, states that the tool’s calculations could help screen photos of victims to confirm their links to a specific offender. “These measurements could be used to find differences or similarities in the facial structure of victims, even with imperfect photos.”
The article talks about the similarities among Ted Bundy’s victims, accepting the notion that he targeted women with long, dark hair parted in the middle—the hairstyle of his mother when he was young and of a woman who’d once rejected him. Not a good foundation. When Bundy heard about this “ subconscious complex,” he scoffed. “They just fit the general category of being young and attractive,” he told investigator Hugh Aynesworth. At any rate, he got his revenge on the woman who’d jilted him. Why target symbolic victims? In addition, during the 1970s, long hair parted in the middle was the leading fashion for young women; it’s more likely than not that his victims would have this style. Even so, not all of them did. And Bundy didn’t select the sleeping victims in the Chi Omega sorority house for their facial features or hairstyle, either. He entered their rooms at random, knowing only that the residents inside would be college girls. The picture is more complex than the concept for this tool suggests.
Even if we grant that some trauma -influenced subconscious force had compelled Bundy’s victim selection, he’s just one of thousands of serial killers. There’s a great deal of variation among them as to MO, motivation , and victim selection. For this Face Similarity Linkage (FSL) to be useful for law enforcement, the database would need significant uniformity, and they’d have to be working on a case that matched the database parameters. This would considerably reduce the tool’s utility, not to mention the scope of its inventors’ claims.
Chapman and team had published a study in 2020 that set the stage. They recognized that only some serial killers target victims based on appearance. Still, the criteria for this subcategory remained unclear. They measured three faces from Ted Bundy’s approximately 30 victims (randomly selected) to produce “anatomical landmarks” for comparison. They found no significant differences among the three, but there were significant differences between this group and a random subject. This apparently served as a “proof of concept,” confirming that with more research, they might one day offer a useful tool for linking serial homicides .
Three victims from one serial killer, measured against one random person. Sounds tenuous.
The more recent research, published in The Police Journal , follows up. This time, they’re more specific about the purpose: The lists of victims of many serial killers might be incomplete. The FSL tool could assist in linking some unsolved cases to a specific offender. The team now states, “It is also common…that many serial killers seek out victims with similar physical characteristics to an opposite- sex parent or close family member who inflicted childhood trauma.”
Common? Where’s the database that supports this statement or offers a percentage? What about the alleged trauma? The speculation that Bundy’s childhood trauma arose from discovering in his teens that his “sister” was really his mother has no evidential support. (Bundy expert Kevin Sullivan told me, “I asked Mike McCann if, in his years of dealing with Bill Hagmaier [an FBI Bundy interviewer], did he ever ask him if Bundy talked about this myth, and Mike said that Hagmaier told him Bundy referred to it as BS.” Still, the researchers pose it as a possible driving force for Bundy’s murders. But again, he’s just one killer out of thousands.
So far, this is unpersuasive. If Bundy is the model, and the hypotheses about his murder motivation arise from unsupported and possibly inaccurate speculations (girlfriend or mother?), there’s no clear basis.
The recent research used three “donor faces” from the Yale Faces Database. Each has nine camera angles. They imported the images into Adobe Photoshop for the measurements and calculations. They made a detailed, highly technical case for the accuracy of biometric calculations, but they didn’t bridge the gap between how it works and how it could link victims to a specific killer. We’d need a list of subjects for whom it might work, and more applications.
Is FSL actually ready? For it to work, the killer-victim linkage would need significant uniformity. Not all serial killers have a victim type, not even those in the subcategory of sexually compelled killers. In addition, those who do have a type might still deviate, depending on circumstances. Dennis Rader described his “perfect victim” as a petite blonde, but only two of his 10 victims matched. He hadn’t even seen four of them before he entered their homes. I can think of other instances, including for Bundy.
The tool might be useful for a killer who strictly sticks with a victim type, is compelled by a trauma that feeds his subconscious motivation, and has more suspected victims. However, FSL couldn’t eliminate a victim, such as one named in a false confession, since even those with preferred victim types might deviate. Glen Rogers targeted red-headed females, but he’s also the prime suspect in the murders of two men.
Until more research with a clearly defined database confirms FSL’s accuracy, the team’s optimism seems premature. While the concept is intriguing, the work thus far lacks the acknowledgment of nuance and variation in killers’ MOs and motivations.
The researchers do admit to the limitations and need for further study, but reporters for popular media who seek sensational headlines apparently ignore this part. The resulting headlines give the false impression that FSL is currently a viable tool in serial murder investigations.
Chapman, B., Keatley, D., & Maker, G. (2026). Development of face similarity linkage for the attribution of intelligence links in unsolved sexually motivated serial homicide. The Police Journal: Theory, Practice, and Principles. https://doi.org/10.1177/0032258X261427252
Hackett, S.B., Keatley, D., & Chapman B. (2020). Face similarity linkage: A novel biometric approach to sexually motivated serial killer victims. Expert Systems , 37:e12597. https://doi.org/10.1111/exsy.12597
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Katherine Ramsland, Ph.D., is a professor of forensic psychology at DeSales University and the author of 69 books.
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