A steel bed frame sits inside 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 of them passed through Tuol Sleng, a former high school converted to a prison by the regime. All but a handful were murdered after an average two months of brutal interrogation. In these cells, prisoners were tortured and sometimes killed while shackled to the bed frames. March 1, 2012.