Serial killer

A serial killer is a mass murderer who kills his victims over a period of time in a series of incidents, as opposed to a spree killer that kills a group over a short period of time in a single incident. The term usually carries the implication that the action is being carried out without the color of government or quasi-government authority, in contrast with the UN Convention on Torture definition that implies the term torture implies the acts are carried out with some form of governmental authority.