 Thirty SS perpetrators at Buchenwald were tried before a US military tribunal in 1947, including Higher SS and Police Leader Josias Erbprinz zu Waldeck und Pyrmont, who oversaw the SS district that Buchenwald was located in, and many of the doctors responsible for Nazi human experimentation.Almost all of the defendants were convicted, and 22 were sentenced to death.However, only nine death sentences were carried out, and by the mid-1950s, all perpetrators had been freed except for Ilse Koch.