Like other RSHA staff, Sattler was assigned to what the head of the RSHA, Reinhard Heydrich, liked to refer to as the "Kämpfende Verwaltung" ("Fighting Administration") - elsewhere identified as Germany's "[paramilitary] taskforces", which were much expanded at the time of the German invasion of the Soviet Union. In this context he seems to have served in Byelorussia and Russia, although even his family was being kept in the dark as to his whereabouts by this point. Between September 1941 and January 1942 Sattler was listed as an "orderly officer" of "Advance Command Moscow" of the Special Commando with "Taskforce Group B". It emerged much later that during 1941 Sattler was a member of the "Einsatzgruppe B" (taskforce) which is believed to have murdered 90,000 in Smolensk. He was later part of an equivalent task force mandated to take over the Interior Ministry in Moscow, but Moscow held out. After "Advance Command Moscow" was dissolved, the unit comprising the survivors was rebranded as "Department SK 7c".