Only about 3,000 inmates remained in the camps when in 1934–35 Heinrich Himmler's SS took full control of the police and concentration camps throughout Germany. It was then that Hitler allowed Himmler to start using the camps' facilities and personnel to purge German society of so-called "racially undesirable elements" such as Jews, criminals, homosexuals, and Romani people (Gypsies, who were thought to spread diseases in their travels across Europe.).