Heinrich Himmler's Schutzstaffel (SS) took full control of the police and the concentration camps throughout Germany in 1934–35.[5] Himmler expanded the role of the camps to hold so-called "racially undesirable elements", such as Jews, Gypsies/Romanis/Sintis, Serbs, Poles, disabled people, and criminals.[6][7][8] The number of people in the camps, which had fallen to 7,500, grew again to 21,000 by the start of World War II[9] and peaked at 715,000 in January 1945.[10]