There were two main Police forces of Nazi Germany under the Reichsführer-SS, Heinrich Himmler from 1936: In September 1939, the SiPo and the Sicherheitsdienst (SD) were folded into the Reichssicherheitshauptamt (RSHA; Reich Security Main Office) where they were made separate departments.
The leadership of the German police was formally vested in the Minister of the Interior, Wilhelm Frick from January 1933, who along with Hermann Göring exercised executive power over Germany's police organs; this was an important part of Adolf Hitler's effort to increase his administrative grip over the nation.
"[2] This action effectively merged the police into the SS and removed it from Frick's control.
[6] Command and control of the Gestapo and the Kripo were since 1936 exerted through Hauptamt Sicherheitspolizei, and from 1939 through the Reichssicherheitshauptamt (RSHA).
[7] These organization along with the Sicherheitsdienst (SD), became departments of the RSHA—initially under Heydrich (1936–1942) and then Ernst Kaltenbrunner (1943–1945) until World War II's end.