It is likely that the mistrust of comrades which had been apparent in Prague will have followed him to Moscow where he fell foul of the Stalin Purges which were intensively focused on German political exiles in Moscow in response to the sudden invasion in June 1941 of the Soviet Union by German forces in defiance of the non-aggression pact negotiated and concluded between the dictator-states two years earlier. On 22 June 1941, Emil Pietzuch was arrested by the homeland security services. He faced trial on 4 December 1943 and was sentenced to five year's loss of liberty. He did not survive his detention, and indeed probably died at the hands of the Gulag in 1943.