In the summer of 1940, the new Sonderdienst battalions were formed in place of Selbstschutz and assigned to the head of the civil administration in the new Gau.[12] The existence of a large paramilitary organization of ethnic Germans with Polish citizenship that engaged in widespread massacres of Poles and helped in the German attack on Poland later served as one of the reasons for the expulsion of Germans after the war.[2] According to German researcher Dieter Schenk, some 1,701 former members of Selbstschutz who committed mass atrocities were identified in postwar Germany.