Hiwis

A Hiwi ([ˈhiːviː]) was a foreigner who volunteered to serve Germany during World War II. The name Hiwis acquired a thoroughly negative meaning following Operation Barbarossa in World War II. Between September 1941 and July 1944 the SS employed thousands of collaborationist auxiliary police recruited as German Hiwis directly from the Soviet POW camps. After training, they were deployed for service with Nazi Germany in the General Government and the occupied East.

In one instance, the German SS and police inducted, processed, and trained 5,082 Hiwi guards before the end of 1944 at the SS training camp division of the Trawniki concentration camp set up in the village of Trawniki southeast of Lublin. They were known as the "Trawniki men" (German: Trawnikimänner). Trawnikis were sent to all major killing sites of the "Final Solution", which was their primary purpose of training. They took an active role in the executions of Jews at Bełżec, Sobibór, Treblinka II, Warsaw (three times), , Lublin, Lvov, Radom, Kraków, Białystok (twice), Majdanek as well as Auschwitz, and Trawniki itself.

...
Wikipedia