Serial killer

A serial killer, as typically defined, is an individual who has murdered three or more people over a period of more than a month, with down time (a "cooling off period") between the murders, and whose motivation for killing is usually based on psychological gratification. Other sources define the term as "a series of two or more murders, committed as separate events, usually, but not always, by one offender acting alone" or, including the vital characteristics, a minimum of at least two ... [ Read More at Wikipedia ]