It was combined, along with the secret state police, the Geheime Staatspolizei or Gestapo into two sub-branch departments of the Sicherheitspolizei (SiPo), which had a central command office known as the Hauptamt Sicherheitspolizei.[3] Reinhard Heydrich was in overall command of the SiPo, including its central command office.[3][4] Arthur Nebe was appointed head of the Reichskriminalpolizeiamt, and reported directly to Heydrich.[5]