Serial Killers and What Makes a Killer

According to the FBI a serial killer is someone who has killed at least three people. The main motive for serial killers, especially sadistic ones, is sexual.


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Modus Operandi

There are three main methods of serial killing. Some killers are nomadic which means they travel around while killing. Others are territorial so they have a hunting ground from which they get their victims. The last type is stationary and stays in one location.

Organized Killers

Organized killers plan ahead. They choose their victim and may even follow or stalk their victim for a while. These killers also clean up after themselves and try to hide evidence. They may even stage a scene to try to trick police.

Disorganized Killers

These killers are more spur of the moment. They take an opportunity when they see it. They will leave behind evidence and rarely try to clean up a crime scene. They do not have a plan and normally blitz attack.


  • Repetitive
  • Time Decreases Between Kills
  • Normally a Single Killer but not Always
  • Extreme Violence
  • Distinguishable Pattern
  • Lack of Motive
  • Increased Mobility


Signature This is something left behind or taken by the killer. It may be on purpose or it may be in the way that they kill. It is something that links the murders. It can evolve but will always be the same.

Cooling off Period There is a period of time between murders when the killer does not kill. This is because the murder no longer satisfies them and they need to kill again. As they kill more and more this period of time normally gets shorter.

Drug Abuse Many serial killers rely on multiple substances. About 45% abuse alcohol while another 7% abuse other drugs. Also a third of studied serial killers had one or more parents who was an alcoholic.

Personality Disorders are common among serial killers. It is often hard to diagnose these during trial though because the insanity defense is often used. Some examples of personality disorders are

  • Narcissistic
  • Antisocial
  • Psychopathic
  • Sadistic
  • Irritable/Explosive
  • Schizoid

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