▁( Foreign ▁Office ), ▁after ▁which ▁he ▁held ▁posts ▁as ▁the ▁commander ▁of ▁the ▁Security ▁Police ▁and ▁SD ▁in ▁the ▁Prote ctor ate ▁of ▁Boh emia ▁and ▁Mor avia ▁under ▁SS - Br iga def ühr er ▁Karl ▁Hermann ▁Frank . ▁ ▁In ▁mid - Oct ober ▁ 1 9 3 9 , ▁E ich mann ▁and ▁St ah le cker ▁decided ▁to ▁begin ▁implementation ▁of ▁the ▁N isko ▁Plan . ▁ ▁On ▁ 2 9 ▁April ▁ 1 9 4 0 , ▁St ah le cker ▁arrived ▁in ▁Os lo , ▁Norway , ▁where ▁he ▁held ▁various ▁posts , ▁most ▁not ably ▁as ▁commander ▁of ▁about ▁ 2 0 0 ▁Einsatz gruppe ▁members ▁of ▁the ▁Security ▁Police ▁and ▁SD . ▁ ▁He ▁was ▁promoted ▁to ▁SS - O ber führ er . ▁ ▁He ▁was ▁succeeded ▁in ▁this ▁position ▁in ▁aut umn ▁ 1 9 4 0 ▁by ▁Heinrich ▁Fe hl is . ▁ ▁Einsatz gruppe ▁A ▁On ▁ 6 ▁February ▁ 1 9 4 1 ▁St ah le cker ▁was ▁promoted ▁to ▁SS - Br iga def ühr er ▁and ▁General major ▁der ▁Pol ize i ▁and ▁took ▁over ▁as ▁command ing ▁officer ▁of ▁Einsatz gruppe ▁A , ▁in ▁hopes ▁of ▁further ing ▁his ▁career ▁with ▁the ▁Reich ▁Main ▁Security ▁Office ▁( R SHA ), ▁Naz i ▁Germany ' s ▁security ▁police ▁and ▁intelligence ▁organization . ▁In ▁June ▁ 1 9 4 1 , ▁Einsatz gruppe ▁A ▁followed ▁Army ▁Group ▁North ▁and ▁operated ▁in ▁the ▁Balt ic ▁states ▁and ▁areas ▁of