It operated from December 8, 1941 – April 11, 1943, parallel to Operation Reinhard during the most deadly phase of the Holocaust, and again from June 23, 1944 – January 18, 1945 during the Soviet counter-offensive. Polish Jews of the Łódź Ghetto and the local inhabitants of Reichsgau Wartheland (Warthegau) were exterminated there.[1] In 1943, modifications were made to the camp's killing methods as the reception building had already been dismantled.[2]