Home Staff of S-21

   The prison had a staff of 1,720 people. Of those, approximateley 300 were office staff, internal workforce and interrogators. The other 1,400 were general workers, including people who grew food for the prison. Several of these workers were children taken from the prisoner families. The chief of the prison was Khang Khek Ieu (also known as Comrade Duch), a former mathematics teacher who worked closely with Khmer Rouge leader Pol Pot. Other leading figures of S-21 were Khim Vat aka Hor (deputy chief of S-21), Peng (chief of guards), Chan (chief of the Interrogation Unit), and Pon (interrogator). Pon was the person who interrogated important people such as Keo Meas, Nay Sarann, Ho Nim, Tiv Ol, and Phok Chhay

The documentation unit was responsible for transcribing tape-recorded confessions, typing the handwritten notes from prisoners’ confessions, preparing summaries of confessions, and maintaining files. In the photography sub-unit, workers took mug shots of prisoners when they arrived, pictures of prisoners who had died while in detention, and pictures of important prisoners after they were executed. Thousands of photographs have survived, but thousands are still missing.

The defense unit was the largest unit in S-21. The guards in this unit were mostly teenagers. Many guards found the unit’s strict rules hard to obey. Guards were not allowed to talk to prisoners, to learn their names, or to beat them. They were also forbidden to observe or eavesdrop on interrogations, and they were expected to obey 30 regulations, which barred them from such things as taking naps, sitting down or leaning against a wall while on duty. They had to walk, guard, and examine everything carefully. Guards who made serious mistakes were arrested, interrogated, jailed and put to death. Most of the people employed at S-21 were terrified of making mistakes and feared being tortured and killed.

The interrogation unit was split into three separate groups: Krom Noyobai or political unit, Krom Kdao or 'hot' unit and Krom Angkiem or 'chewing' unit.The hot unit (sometimes called the cruel unit) was allowed to use torture. In contrast, the cold unit (sometimes called the gentle unit) was prohibited from using torture to obtain confessions. If they could not make prisoners confess, they would transfer them to the hot unit. The chewing unit dealt with tough and important cases. Those who worked as interrogators were literate and usually in their 20s

Some of the staff who worked in Tuol Sleng also ended up as prisoners. They confessed to being lazy in preparing documents, to having damaged machines and various equipment, and to having beaten prisoners to death without permission when assisting with interrogations.