Einsatzgruppen
In June 1941, Heinrich Himmler, the leader of the SS, told other SS leaders that the Nazis planned to kill up to 30 million people in the Soviet Union.  The Einsatzgruppen would play an important part in this by murdering people who the Nazis thought were inferior.  However, the Nazis would also use other strategies, like starvation, to kill other Soviets.p. 181