In fact the Germans employed kapos (other prisoners) to do the dirty work.
https://www.jewishvirtuallibrary.org/jso...kapos.html
https://www.jewishvirtuallibrary.org/jso...kapos.html
Quote:The German concentration camps depended on the cooperation of trustee inmates who supervised the prisoners. Known as Kapos, these trustees carried out the will of the Nazi camp commandants and guards, and were often as brutal as their SS counterparts.