Sonderkommando

Sonderkommandos were work units made up of German Nazi death camp prisoners. They were composed of prisoners, usually Jews, who were forced, on threat of their own deaths, to aid with the disposal of gas chamber victims during the Holocaust. The death-camp Sonderkommandos, who were always inmates, were unrelated to the SS-Sonderkommandos, which were ad hoc units formed from members of various SS offices between 1938 and 1945. (Wikipedia)