Heinz Paul Johann Felfe was a German spy. At various times he worked for the intelligence services of Nazi Germany, Great Britain, the Soviet Union and West Germany. It is still not clear when he started working for Soviet intelligence, but it is known that between 1951 and 1961 he was a highly effective double agent, supplying important intelligence received in the course of his work for West German Intelligence to the Soviet Union. As a younger man, starting in 1936, Felfe served in the SS, most recently as an Obersturmführer.

https://en.wikipedia.org/wiki/Heinz_Felfe