This led to Heiden having to resign as head of the SS.[2] Historian Adrian Weale says that the dismissal was probably because he was ineffective in the job, but there also were rumors that he was a police informer.[24] Himmler's biographer Peter Longerich says that beyond the official announcement "we have no further clues to explain either Heiden's dismissal or Himmler's appointment".[25] Under Himmler the SS greatly expanded over time, with his ultimate aim being the one to turn it into the most powerful organization in Germany.[26]