Skip to main content

Verified by Psychology Today

Serial Killers

Understanding What Drives Serial Killers

Their individual motives vary greatly.

Public Domain
Jeffrey Dahmer Milwaukee Police 1991 Mugshot
Source: Public Domain

Many serial killings seem to be completely devoid of meaning or motivation on the part of the criminal. In actuality, however, there is great diversity in the needs and desires of serial killers that lead them to extinguish the lives of others. Sometimes, the act or process of murder can be an end in itself for them.

One aspect of popularly held beliefs and media stereotypes that often holds true is that most serial killers derive great satisfaction from the act of killing. The gratification they receive from the act of murder differentiates them from one-time murderers who kill incidentally—that is, to help commit or conceal another crime. Stated differently, serial killers have a chronic and overwhelming need to commit murder that distinguishes them from those who kill one time because it serves other criminal interests.

It may seem to be counterintuitive on the surface but many serial killers are actually insecure individuals who are compelled to kill due to a morbid fear of rejection. In many cases, the fear of rejection seems to result from having been abandoned by their mother in early childhood.

Infamous serial killers who were rejected or abandoned by their birth mothers include David Berkowitz, Ted Bundy and Joel Rifkin. Some serial killers such as Edmund Kemper are tormented, abused and even tortured by their birth mothers.

A neophyte serial killer who was traumatized as a child will seek to avoid painful relationships with other human beings as an adult. He will particularly seek to avoid painful relationships with those he desires or covets. Such fear of rejection may compel a fledgling serial killer to want to eliminate any objects of his affections. He may come to believe that by destroying the person he desires prior to entering into a relationship with them, he can eliminate the frightening possibility of being abandoned, humiliated or otherwise hurt by someone he loves, as he was in childhood.

As explained by the FBI in a 2005 report on serial homicide, a serial killer selects victims based on availability, vulnerability and desirability (1).

Availability is primarily determined by the lifestyle of the victim or circumstances in which he/she is involved that may provide the offender access for an attack. For example, a single female who regularly spends her evenings alone at home is available for a break-in attack by a serial predator.

Vulnerability is defined as the extent to which the victim is at-risk or susceptible to attack by the offender. A single female walking down the street at night is less vulnerable to attack if she is accompanied by a large dog.

Desirability is highly subjective and is described as the attractiveness or appeal of the victim to the offender. Victim desirability involves numerous factors related to the motivation of the offender and may include characteristics such as race, ethnicity, gender, age, body type or other specific criteria established by the serial killer.

At a symposium on serial homicide in 2005, the FBI and other experts in criminology and forensic psychology had an in-depth discussion about the motivations of serial killers. The attendees made a number of observations and recommendations for serial homicide investigations that are related to the motivations of the killer.

As presented by the FBI in Serial Murder: Multi-Disciplinary Perspectives for Investigators, the specific observations made by attendees at the symposium are outlined below (1).

  • The motive can be very difficult to determine in a serial murder investigation.
  • A serial murderer can have multiple motives for committing his/her crimes.
  • A serial killer’s motive(s) can evolve both within a single murder and throughout the series of murders.
  • The classification of motivations should be limited to observable behavior and conditions at the scenes of the murders.
  • Even if a motive can be identified, it may not be helpful in identifying a serial murderer.
  • Utilizing investigative resources to discern the motive instead of identifying the offender can derail or bog down an investigation.
  • Investigators should not necessarily equate a serial murderer’s motivation(s) with the level of injury.

Finally, regardless of the specific motive(s), most serial killers commit their crimes because they want to. The exception to this would be those few serial killers suffering from a severe mental illness for whom no coherent motive exists.

The attendees of the 2005 FBI symposium on serial murder suggested that broad, non-inclusive categories of motivation be utilized as guidelines for criminal investigation. They argued that such categories can assist law enforcement authorities in narrowing the pool of suspects in a serial homicide case. The attendees at the symposium identified seven general categories of motivation to be used as guidelines for investigative purposes.

The categories are not intended to be a complete measure of serial offenders, nor are they intended to comprise a theory of their motivation. As concisely reported by the FBI in 2005, they are listed below.

  • Anger is a powerful motivation in which the offender displays rage or hostility toward either a certain subgroup of the population such as the homeless or society as a whole.
  • Criminal enterprise is a motivation in which the offender benefits in status or monetary reward by committing murder that is drug, gang or organized crime-related. For example, murder may be perpetrated by a drug gang in order to eliminate its competition.
  • Financial gain is a motivation in which the offender benefits monetarily from killing that is not drug, gang or organized crime-related. A few examples of these types of crimes are comfort/gain killings, robbery-homicide or multiple killings involving insurance or welfare fraud.
  • Ideology is a motivation to commit murder in order to further the goals and ideas of a specific individual or group. Examples of these include terrorist groups or an individual(s) who attacks a specific racial, gender or ethnic group out of sheer hatred for the group.
  • Power/thrill is a motivation in which the offender feels empowered and/or exhilarated when he kills his victims. The act of killing is an end in itself.
  • Psychosis is a rare situation in which the offender is suffering from a severe mental illness and is killing specifically because of that illness. The condition may include auditory and/or visual hallucinations and paranoid, grandiose or bizarre delusions.
  • Sexually-based is a motivation driven by the sexual needs or desires of the offender. There may or may not be evidence of sexual contact present at the crime scene.

It is important to remember that regardless of the specific motive(s), serial killers are compelled to commit murder—that is, they do it because they want to and need to.

Dr. Scott Bonn is a criminologist, professor, and media expert.


1) Morton, R.J. 2005. Serial Murder: Multi-Disciplinary Perspectives for Investigators. National Center for the Analysis of Violent Crime. Washington, D.C.: U.S. Department of Justice.

More from Scott A. Bonn Ph.D.
More from Psychology Today