A metal bed frame and artifacts from the Khmer Rouge era occupy a detention cell for high-ranking party cadres at the Tuol Sleng prison in Phnom Penh, Cambodia. As many as 2 million Cambodians -- or one-quarter of the population -- died under the Khmer Rouge from 1975 to 1979. An estimated 17,000 political detainees passed through Tuol Sleng, a former high school converted to a prison by the regime. All but a handful of those were murdered in the Killing Fields after months of brutal interrogation. In these cells, the victims were often tortured and sometimes killed while shackled to the bed frames. March 21, 2012.