The Sicherheitsdienst (SD) was the intelligence agency of Nazi Germany and the Nazi Party from 1932 to 8 May 1945. The party was a branch of the SS and a sister organization of the Gestapo, and it was an independent SS office from 1933 to 1939 before becoming a part of the Reich Main Security Office. SD director Reinhard Heydrich intended for the SD to keep every single individual in Nazi Germany under continuous supervision, and the SD was declared a criminal organization during the Nuremberg Trials. Heydrich's successor, Ernst Kaltenbrunner, was executed for crimes against humanity.