A death squad is an armed group that conducts extrajudicial killings or forced disappearances of persons for the purposes of political repression, genocide, or revolutionary terror. These killings are often conducted in ways meant to ensure the secrecy of the killers' identities. Death squads may have the support of domestic or foreign governments (see state terrorism). They may comprise a secret police force, paramilitary groups, government soldiers, policemen, or combinations thereof. They may also be organized as vigilantes. When death squads are not controlled by the state, they may consist of insurgent forces or organized crime.
Historically, the origins of what are modernly known as 'death squads' goes back many decades to the Bolshevik Cheka as a part of the Red Terror in Russia. The Cheka were initially a party organization and later were given official powers and authority for extrajudicial secret arrest, internment, and execution. They ultimately institutionalized the practices into the Gulag system.
Einsatzgruppen were used by Nazi Germany as a part of the Holocaust. The Nazi squads, composed of police officers mixed in with other agents, killed Jewish civilians and political opponents, going through captured territory that the regular German army had previously taken.
Although the term "death squad" did not rise to notoriety until the activities of such groups in Central and South America during the 1970s and 1980s became widely known, death squads have been employed under different guises throughout history. Apparently, the term was first used by the fascist Iron Guard in Romania. It officially installed Iron guard death squads in 1936 in order to kill political enemies. It was also used during the Battle of Algiers by Paul Aussaresses.