Serial killer

A serial killer is typically a person who murders three or more people, usually in service of abnormal psychological gratification, with the murders taking place over more than a month and including a significant period of time between them. While most authorities set a threshold of three murders, others extend it to four or lessen it to two.

Psychological gratification is the usual motive for serial killing, and most serial killings involve sexual contact with the victim, but the Federal Bureau of Investigation (FBI) states that the motives of serial killers can include anger, thrill-seeking, financial gain, and attention seeking. The murders may be attempted or completed in a similar fashion. The victims may have something in common, for example, demographic profile, appearance, gender or race.

Although a serial killer is a distinct classification that differs from that of a mass murderer, spree killer, or contract killer, there may be conceptual overlaps between them and some debate exists on specific qualifications, especially with regard to spree killers in comparison to serial killers.