Recruited from professional police officers, its role and organisation was quickly established by Hermann Goering after Hitler gained power in March 1933. Rudolf Diels was the first head of the organization, initially called Department 1A of the Prussian State Police.
The role of the Gestapo was to investigate and combat "all tendencies dangerous to the State." They had the authority to investigate treason, espionage and sabotage cases, and cases of criminal attacks on the Party and State.
The Gestapo's actions were not restricted by the law or subject to judicial review. The Nazi jurist, Dr. Werner Best, stated, "As long as the [Gestapo]... carries out the will of the leadership, it is acting legally."
The power of the Gestapo most open to misuse was Schutzhaft or "protective custody" - a euphemism for the power to imprison people without judicial proceedings, typically in concentration camps.
In 1934, Goering, under pressure from Heinrich Himmler, agreed to grant control of the Gestapo to the SS. In 1936 Reinhard Heydrich became head of the Gestapo and Heinrich Muller chief of operations.
During World War II, the Gestapo was expanded to around 45,000 members. It helped control conquered areas of Europe and identify Jews, Socialists, homosexuals and others for transportation to camps.
At the Nuremberg Trials the entire organisation was charged with crimes against humanity.