Police Battalion 309 was subordinated to the German Army's 221st Security Division.[4] Comprising about 550 men, the battalion was raised from recruits mobilised from the 1905–1915 year groups. They were led by career police professionals, steeped in the ideology of Nazism, driven by anti-semitism and anti-Bolshevism.[5] The 221st Security Division itself was formed in June 1941.