SS General Hans Kammler, who as an engineer had constructed several concentration camps, including Auschwitz, had a reputation for brutality and had originated the idea of using concentration camp prisoners as slave laborers in the rocket program. Arthur Rudolph, chief engineer of the V-2 rocket factory at Peenemünde, endorsed this idea in April 1943 when a labor shortage developed. More people died building the V-2 rockets than were killed by it as a weapon. Von Braun admitted visiting the plant at Mittelwerk on many occasions, and called conditions at the plant "repulsive", but claimed never to have personally witnessed any deaths or beatings, although it had become clear to him by 1944 that deaths had occurred. He denied ever having visited the Mittelbau-Dora concentration camp itself, where 20,000 died from illness, beatings, hangings, and intolerable working conditions.