The Einsatzgruppen (Special Action Groups) was used behind the front line on the Eastern front to kill primarily Jews, (active) communists, partisans and people suspected of helping the partisans.

Naturally the brutal methods of the Einsatzgruppen made the people in the occupied territories more and more sympathetic to the partisans and thus made it all the harder for the Germans to protect their lines of communications.

Einsatzgruppen Chain of Command
ReichsSicherheitsHauptAmt (RSHA)
Befehlshaber der Sipo under des SD-BdS
Kommandeure der Sipo und des SD-KdS
(400 - 1.000 men)
Sonderkommandos or Vorkommandos

The men that made up the Einsatzgruppen came for various organisations, such as the Polizei (police), Waffen-SS and the Gestapo.

Einsatzgruppe A was made up as follows in October 1941:
Administration 18
Auxiliary Police 87
Females 13
Gestapo 89
Interpreters 51
Kriminalpolizei 41
Motorcyclists 172
Ordnungspolizei 133
Radio operators 8
Sicherheitsdienst 35
Teletype operators 3
Waffen-SS 340