S21: The Khmer Rouge Killing Machine (2003) is a Documentary, History, War film that follows documentary of the S-21 genocide prison in Phnom Penh with interviews of prisoners and guards. On the search for reasons why this could have happened. S21: The Khmer Rouge Killing Machine is not currently listed with streaming providers in your selected region, but availability can change over time. It has a user rating of 7.5 out of 10 from 35 votes. Fans of documentary movies may also want to explore similar titles below.