Reich Security Main Office:

The Reich Security Main Office, or Reichssicherheitshauptamt in German, was another Nazi organization led by Heinrich Himmler, who was Chef Der Deutschen Polizei (Chief of German Police) and Reichsführer (Reichs Leader). The duty of this organization was to eliminate all opponents, political or non-political, inside and outside of Nazi Germany. The Reich Security Main Office was very important in the Reich, in both orchestrating and executing the Holocaust.

Heinrich Himmler established the RSHA on September 27, 1939. He wanted the police and security departments of Nazi Germany to be under one organization, as the police and security played a key role in the growth of the Reich's power. He also unified the Nazi Party's Sichherheitsdienst (SD/Intelligence Service) and the Sichherheitspolizei (SiPo/SS Security Police) under one organization as a whole. The SiPo was an organization within the RSHA consisting of two sub-departments, these were the Geheime Staatspolizei (Gestapo/Secret Police) and the Kriminalpolizei (Kripo/Criminal Police). The RSHA was shortened to RSi-H, to avoid confusion yet again with another division: the SS-Rasse- und Siedlungshauptamt (RuSHA/SS Race and Settlement Office).

When the RSHA was established, it represented the formalization of the relationship of the SD, which in this case, served as the Intelligence Agency for the Gestapo. Something similar existed in the local offices in Nazi Germany, where the Gestapo, Criminal Police, and SD were separate from each other, because they had their own purpose in the RSHA. 

The RSHA did indeed, like many other divisions, continue to advance and grow at an astonishing rate during the Second World War. The RSHA's reorganizations did not change the tendency of the centralization of the Third Reich, not following the leader-follower pattern of Germany's conduct. Departments within the RSHA such as the SD and the Gestapo were directly controlled by Heinrich Himmler and Obergruppenführer Reinhard Heydrich, who were apparently above the law and had control over life and death of almost every German. Heydrich remained the head of the RSHA until his death in 1942, and then Himmler gave the position to Obergruppenführer Ernst Katenbrunner, who kept the position until the end of the war in Europe.

Reinhard Heydrich:

Reinhard Heydrich was born on March 7, 1904 in Halle, Germany. He served in the SS Battalion as Heinrich Himmler's Chief Lieutenant. After Adolf Hitler was elected Chancellor of Germany in 1933. Heydrich was appointed Chief of the Political Department of Munich's police. Heydrich was ranked up a lot in the SD. He was chosen to be Chief of the SS for Berlin in 1934. Heinrich Himmler became head of all German Police Forces in 1936.  Heydrich became chief of the Criminal Police, the SD, and the Gestapo. 

Heydrich committed a lot of war crimes and terrible things. He ordered many arrests for Jews and they were sent to Concentration Camps where they were never seen again. In 1939 Heydrich was appointed head of the RSHA (Reich Security Main Office).  Meaning he was in charge of all of the secret police of Nazi Germany. Heydrich and Eichmann organized the first deportation of the Jews in Germany. Hermann Goring commissioned Heydrich as the one to administrate the extermination of the Jews.

In September of 1941. Heydrich was given Reichsprotektor of Bohemia and Moravia. He failed his security, and then on May 27, 1942, two Czech agents badly wounded Heydrich with a bomb while he was riding in his car without any escort. The team was trained by the British Special Operations Executive, or SOE, and was given the approval by the Czechoslovak president Edvard Beneš to carry out the assasination.  And on June 4, Heydrich died in a Prague hosiptal.