In the U.S., 65% of serial killers kill for pleasure, but less than 1% kill because of psychosis.
Domination, punishment, fantasy fulfillment—these are just some of the motives that underlie serial killers’ justifications for committing serial homicide. The serial killer’s inner world is one of dark obsession, need, and torment, where ritualism and insatiable desire fuel compulsions. The considerably low rate at which known serial homicides are committed (as opposed to the 45.6 percent of isolated homicides involving a single offender and victim) present challenges for American criminal justice practitioners seeking to conceptualize the social, psychological, and situational forces that drive this disturbing and repetitive behavior.
One surprising obstacle in conceptualizing serial homicide is that experts historically have disagreed on the technical definition of a serial killer, specifically the number of homicides committed by the offender and the temporal aspects involved. For investigative and research purposes, the FBI’s definition of serial killing is the most widely accepted one today. The FBI currently defines serial killing as “the unlawful killing of two or more victims by the same offender(s), in separate events.”
In the late 1970s and early 1980s, the FBI initially developed a three-category system for multiple homicide types, which, in addition to serial murder, included the categories of mass murder and spree killing. In 2005, FBI experts discontinued spree killing as a category. At that time, spree killing was differentiated from serial killing based on the “cooling-off” period that occurred between murders. By this definition, spree killings lacked a cooling-off period—they constituted a single continuous event.
The discontinuation of the spree killing classification was due to the difficulty in standardizing a timeframe in which the killings could occur, which resulted in inconsistent classifications of multiple homicide events by criminal justice practitioners. The FBI currently recognizes the multiple homicide types as serial murder and mass murder, with mass murder differing from serial murder in that it requires more than four victims to be unlawfully killed by the same offender during one event. This article is focused exclusively on serial killer motives based on known instances of serial murder within the United States.
Classic Serial Killer Motive Categories
In 1988, Ronald Holmes and James DeBurger classified serial killer motives into four core categories: Hedonistic, Power/Control, Mission-Oriented, and Visionary. These classic categories and their corresponding sub-motives are somewhat broad and intended to guide investigatory processes such as criminal profiling. These motive categories may not fully encompass the primary motivations of all American serial killers. According to a 2023 report on Serial Killer Statistics, in approximately 10.6 percent of all known instances of serial homicide, experts categorize the perpetrator as having multiple motives rather than identifying a singular primary motive.
These categories and motives can blur even further in the rare cases where serial killers commit their heinous crimes in pairs, such as when romantic couples kill.
Hedonistic Serial Killer Motives – 65.3 Percent of Serial Killings
The most common serial killer motive type, hedonistic serial killer motives, stems from an offender’s pursuit of satisfaction and pleasure. Hedonistic motives can be further designated by the type of gratification sought by the offender. The 2023 Annual Report, released jointly by Radford University/Florida Gulf Coast University, specifies categories of Financial Gain, Enjoyment – Rape, Enjoyment – No Rape — all of which fall under the hedonistic motives umbrella.
Another motive experts frequently observe within the hedonistic motives group is sexually based killings, where the offender is motivated to kill from a place of gratifying their sexual needs and desires. It is important to note that sexual contact reflected in instances of serial killing may not necessarily reflect overt sexual contact, as in cases such as the ‘Night Stalker’ Richard Ramirez. We also often observe thrill-based motives, where the offender seeks the excitement and empowerment that accompanies their commission of murder.
One classic example of a hedonistic serial killer is Jeffrey Dahmer, the famous cannibal, whose crime components of sadomasochism and fetishism increased in tandem with his escalating need for sexual stimulation. Jeffrey Dahmer’s fantasy of acquiring his idea of a perfect lover fueled his murder and cannibalism of seventeen boys and men. Ed Kemper is another well-known example of a hedonistically motivated serial killer, exemplified through his many acts of necrophilia. In contrast, Jack Unterweger (one of the serial killers who spent time at the famed Cecil Hotel) was a classic thrill-seeking serial killer. Further, the case of Ian Brady embodies both the adrenaline-seeking behavior of thrill-based serial killers and sexual gratification.
Power/Control Serial Killer Motives (Anger) – 16.5 Percent of Serial Killings
The second most common category of serial killer motives within the United States is power/control motives. Power/Control motives stem from an offender’s desire to assert authority and totally dominate their victims. Anger is a subtype of this category that is commonly observed, characterized by the offender’s displays of hostility. Rather than being motivated solely by the pursuit of sexual gratification, power/control motivation aligns more with the offender’s fantasy fulfillment of omnipotence.
An example of a power/control motivated serial killer is Ted Bundy, who intentionally chose victims he was confident he could overpower. He also sought to exert control over law enforcement’s investigatory processes by attempting to avoid detection by moving between multiple states. Another example of a power/control motivated serial killer is Dennis Rader, the “BTK Killer”, who indulged his urge to exert total control over his victims by stalking them for weeks before murdering them within their own homes. His modus operandi included strong elements of binding, torturing, and killing his victims (hence the “BTK” name). Dennis Rader also demonstrated controlling behaviors by taunting the media and law enforcement with letters containing clues regarding his killings, all part of his grand illusion of control.
Mission-Oriented Serial Killer Motives – Approximately 10.6 Percent of Serial Killings
Mission-oriented serial killers justify their killings through beliefs that they are benefiting society and/or serving a higher power with their actions. The most recognized subtype within this category is the motive of ideology, when the offender seeks to further goals and/or ideas of an individual or group. Another mission-oriented subtype is criminal enterprise, typically associated with gangs, drug trafficking, or organized crime syndicates. In these instances, the offender benefits through increased gang status, demonstration of gang loyalty or other aspects through the commission of serial murder. Serial killer Timothy Joseph McGee was a high-ranking member of the Toonerville Rifa 13 gang who was alleged to be responsible for at least twelve gang-related homicides and convicted of three.
Ted Kaczynski, the Unabomber, exemplifies a classic mission-oriented serial killer—his targeted bombings, which killed three and injured many, were intended to catalyze his own political and social agendas. Ted Kaczynski’s radical anti-technology viewpoints supported his plan to dismantle the industrial-technological system through forced revolution. Joseph Paul Franklin was also mission-oriented and was motivated by white supremacist ideology, which he used as justification to target individuals who were biracial, Black, and Jewish.
Visionary Serial Killer Motives – Approximately 0.5 Percent of Serial Killings
Visionary motives are the rarest serial killing motive observed within the United States. In these instances, the offender commonly suffers from various delusions and/or visual and auditory hallucinations due to mental illness. These particular killings are usually highly disorganized, and the commission of murder itself is the primary goal of visionary-motivated serial killers. Often, these offenders believe they are killing on behalf of entities such as God or even the Devil. A classic example of a visionary-motivated serial killer is David Berkowitz, the “Son of Sam”, who terrorized New York City in 1976 and 1977. He killed six people and injured several others, according to EBSCO. Berkowitz claimed he had done so directly under the orders of the devil.
Statistical Overview of the Motives Behind Serial Killing in the United States
At the time of this article’s publication, the Radford/FGCU 2023 Annual Report is one source that provides the cumulative data on serial killers in the United States. Obscurix remains committed to ongoing crime trend analysis, and will supplement/update these findings in the future when more data becomes readily available.
- Enjoyment (Overall) – 35.6 percent (Enjoyment – Rape: 23.6 percent, Enjoyment – No Rape: 7.4 percent, Enjoyment – Other: 4.6 percent)
- Financial Gain – 29.7 percent
- Anger – 16.5 percent
- Psychosis/Visionary motives – Approximately 0.5 percent
- Multiple Motives – Approximately 10.6 percent
- Unaccounted/Other – Approximately 7.1 percent
Example: Faye and Ray Copeland’s entire serial killing operation was financially motivated, where they murdered transients whom they’d previously employed as part of a cattle theft scheme.
Gendered Differences in Serial Killing Motives
Please note that the following differences in serial killing motives based on gender are reflective of the publicly available data relative to male and female offenders. Obscurix acknowledges the limitations inherent in the male-female binary-centric nature of historical crime data in the United States. These frameworks impact our understanding of crime patterns across the gender spectrum. We acknowledge the need for more gender inclusive crime research to facilitate a more accurate representation of modern offending patterns.
“69.6 percent of females killed for financial reasons as opposed to 28.3 percent of men.“
Both male and female serial killers are motivated by the hedonistic motive subtype of financial gain. Still, this motive comprises significantly more instances of serial killings for female offenders than their male counterparts. Specifically, 69.6 percent of females killed for financial reasons as opposed to 28.3 percent of men. The second most common motive for male serial killers is enjoyment (rape) at 27.7 percent, followed by the third most common motive of anger at 17.8 percent.
Interestingly, female offenders commit a similar percentage of anger-motivated serial killings at 17.5 percent, which is the second most common motive for females. Enjoyment (no element of rape present) is the primary motive in 5.3 percent of serial homicides committed by females. Crime statistics indicate that male serial killers are more likely to implement torture, mutilate their victims after death, cannibalize their victims, and engage in necrophilia than their female counterparts.
Victimology profiles also indicate that female serial killers are inclined to victimize both females and males, whereas male offenders primarily target females. Male serial killers are commonly not related to their victims and are more likely to victimize adults. In contrast, female serial killers most frequently target family members and are more likely to kill children and infants compared to their male counterparts. This is relevant in the context of crime motive because it enables us to better understand offender methodologies in relation to victim selection.
Primary Motives of Male Serial Killers
- Financial Gain – 28.3 percent
- Enjoyment (rape) – 27.7 percent
- Anger – 17.8 percent
- Enjoyment (no rape) – 8.2 percent
- Criminal Enterprise – 5.8 percent
- Multiple Motives – 12.2 percent
Primary Motives of Female Serial Killers
- Financial Gain – 69.6 percent
- Anger – 17.5 percent
- Enjoyment (no rape) – 5.3 percent
- Enjoyment (rape) – 3.7 percent
- Criminal Enterprise – 0.5 percent
- Multiple Motives – 3.5 percent
Racial Differences in Serial Killing Motives
“Across all time periods, approximately half of serial killers have been White, 41 percent Black, 7 percent Hispanic, 1 percent Asian, 1 percent Native American.” The primary motives of White serial killers are hedonistic in nature, the most common motive being financial gain behind approximately 32.3 percent of serial killings, followed by enjoyment (element of rape present) at approximately 28.2 percent. The primary motives of Black serial killers were also hedonistic subtypes, mainly financial gain (approximately 29.8 percent), followed by enjoyment (approximately 22 percent).
Additionally, the mission-oriented motive subtype of gang/criminal enterprise was significantly higher among Black serial killers than their White counterparts, approximately 9.8 percent vs. 1.7 percent, comparatively. White offenders “were more likely to kill only White victims (81.9 percent), whereas only 43.3 percent of Black serial killers killed only Black victims”. Obscurix recognizes the small sample size of serial killers as a clear limitation to data interpretation of racial differences in serial killing motives, which makes data for all racial/ethnic groups difficult to aggregate and analyze.
Data Limitations on Serial Killing Motives
We must be mindful of the potential for methodological biases within crime data collection, specifically the overemphasis of psychiatric and psychological factors, and the underrepresentation of the sociological aspects in serial homicide data. Criminal justice practitioners have traditionally demonstrated an overreliance on descriptive statistics over empirical data analysis. A lack of understanding regarding the idiosyncrasies of all American serial killers subsequently limits our ability to fully interpret serial homicide data.
Additionally, when attempting to understand the driving forces behind serial killing, motives may not be clearly identifiable. Another phenomenon we must consider is the behavioral inconsistency of serial killers and its impact on motive interpretation and classification. That is, killings may outwardly appear to be the work of multiple offenders, but in actuality may be the work of a singular offender whose criminal behaviors changed as they attempted to prioritize multiple serial killer motives simultaneously, or as they completely shifted their original primary motive to another.
Finally, there are logistical considerations to consider. Often, serial killers in custody sit on death row and may not be cooperative with in-depth psychological examinations, or the state may execute them before every psychological truth can be analyzed. They may also manipulate interviewers or provide false information.
Serial Killer Motives Conclusion
The motives for serial killing are often nuanced. However, one universal truth remains – understanding why offenders are motivated to commit their crimes brings us one step closer to more accurately conceptualizing the modern American serial killer.
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