During the Cambodian Genocide (1975–79), about 12,272 to 20,000 people were jailed in the infamous Tuol Sleng (S-21) prison. Only a handful survived. This study focuses on how former S21 perpetrators relate today to their role in the genocide. Through a vast network of fear and torture, the Khmer Rouge instituted a program of “thought reform” in order to accomplish total obedience. Based on court testimonies, archival material, and semi-structured interviews with surviving S-21 guards and interrogators, this study shows how the former S-21 personnel manifest a lingering obedience orientation toward authority, limited reflection about the past, and little empathy toward their victims. The study demonstrates the long-lasting implications of the mindset that was established by the Khmer Rouge. More needs to be done to face the past and to “remove the guards from their prisons” in Cambodia.