How to Classify a Serial Killer
There's more than one way to categorize serial killers.
Updated March 31, 2026 | Reviewed by Devon Frye
People like typologies. They simplify complex subjects and make them easier to discuss.
Sometimes, a typology will seem to be the standard. Look up “types of serial killers ,” and you’ll likely get the classification system that Holmes and DeBurger offered in 1988. They proposed four types of serial killers: visionary, mission-oriented, hedonistic , and power/control-oriented . It’s loosely based on four distinct driving motivations.
However, it’s not the only typology. Crime historian Philip Jenkins proposed a simpler one: the predictable type (a clear progression from antisocial behavior to serial murder) and the respectable type (an unexpected turn to serial murder). During the 1980s, the FBI focused on an organized/disorganized continuum, while forensic psychiatrist Park Dietz grouped these offenders as psychopaths, psychotics, and custodial.
In part, the lack of consensus is complicated by the shifts in the definition of a serial killer. The criteria began to form for law enforcement in the 1970s, with the FBI’s budding Behavioral Science Unit leading the way (although the term was in use well before the unit was established). These agents studied repeat multicidal killers for their teaching curriculum.
They initially stipulated three or more victims in three or more locations, considered separate but linked events, with a “cooling off” period between them. By 1992, the requirement for three locations was dropped for The Crime Classification Manual , which states : “Serial murders involve three or more separate events, with an emotional cooling off period between homicides.” No specific motive or MO was mentioned.
Still, some criminologists argued that motivation helped to distinguish a specific type of offender from those who commit multiple murders but would not qualify as serial killers (e.g., those in gangs or organized crime syndicates). In addition, some criticized the concept of “cooling off” as vague. What does this look like? How long does it last?
To address these issues, in 2005, the agency organized a symposium for law enforcement, academics, and clinicians. According to one organizer, the participants agreed that the lowest possible minimum number of victims would offer the greatest flexibility for law enforcement and still be useful for research. Since serial killers had diverse motivators, it seemed expedient to dispense with motivation. The FBI announced its final definition: The unlawful killing of two or more victims by the same offender(s), in separate events.
That’s pretty broad—some say too broad to be useful for research. Still, it leaves open the question of typologies. There’s no reason to accept the first one that comes up on an internet search. Among the choices for developing categorical criteria are motive, MO, victim type, age, sex, location, psychiatric conditions, and historical period.
Perhaps the most familiar type of serial killer is the lust murderer. In this category are John Wayne Gacy, Jeffrey Dahmer, Ted Bundy, Dennis Rader, Danny Raines, and Edmund Kemper. Lust murder becomes addictive and can trigger escalation.
Many lust killers have paraphilias, or sexual deviancies. Peter Kurten drank blood, and Joachim Kroll consumed parts of children. Jeffrey Dahmer and Dennis Nilsen both merged their arousal over corpses with the need to relieve their isolation. Jeanne Weber derived sexual ecstasy from choking children.
Some killers have said that to take a human life makes them feel superior, like God. The sense of domination is euphoric. The Beltway Snipers of 2002 made this claim, as did Bobbie Joe Long, the Zodiac, and Ted Bundy. While sexual activities may be involved, the feeling of total control was the stated primary driving force.
But there are other motives, which I note in my own typology. Some killers just want publicity, attention , and fame. Colin Ireland and Dennis Rader both studied other killers to follow the “right” way to gain some glory.
On the other hand, some are driven by anger , greed, or hatred. Paul John Knowles began to kill when his fiancée rejected him. Carl Panzram reacted to perceived abuse, and Todd Kohlhepp was angry about many things.
I even included a few killers who claimed that murder was an intellectual exercise. Some said they had no particular reason at all. Some participated in murder because they’d hooked up with a violent partner, and some claimed they’d killed out of a sense of mercy.
Renowned serial killer researcher Harold Schechter provides a typology based on MO: Bludgeoning, stabbing or cutting (usually knives or axes), poisoning, firearms, bombs, asphyxiation, and mixed. Within these might be subtypes, such as those who took trophies like jewelry, took body parts, or took neither. Or those who left bodies where they lay vs. transporting them to a specific site. Those who operated as a team vs. lone wolves. Those who calculated their approach vs. those who were sloppy.
Essentially, there are many ways to classify serial killers. At this time, no one has a definitive system. The categories one might use for simplifying discussions about serial killers are those that best serve a specific purpose.
Holmes, R. M., & DeBurger, J. (1988). Serial murder. Studies in Crime, Law and Justice, 2 .
Ramsland, K. (2021, May). American serial killers : A critical analysis. Criminal Law and Criminal Justice Books .
Ramsland, K. (2004). Inside the minds of serial killers: Why they kill . Praeger.
Schechter, H. (2003). The serial killer files . Ballantine.
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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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