In 1950/51 Heinz Felfe was also working for the West German government in Bonn with the Federal Ministry for intra-German relations. The zones of occupation agreed upon between the principal allied leaders at Potsdam had by now crystallized in such a way that the Soviet occupation zone had been developed into a separate stand-alone state; for the first few years after 1945 under Soviet administration and, since the young country's foundation in 1949, as the German Democratic Republic (while still able to access the fraternal security advice and practical support of several hundred thousand resident Soviet troops). The frontier between the two German states later became famously fortified, but through the later 1940s and early 1950s large numbers of people moved with little impediment from East Germany to West Germany. Inevitably some of those making the crossing would turn out to have been sent across to gather information for the East German and Soviet intelligence services. Felfe was employed as an interrogator, tasked with screening, among others, former members of East Germany's quasi-military police service ("Volkspolizei") and any identified associates arriving in the refugee camps.