Mr. SUOS Thy
The Witness worked at S-24 (Prey Sar) before being transferred to the main S-21 compound in early 1976,
where he became Head of the Documentation Unit. He was responsible for recording names, compiling
biographies, and photographing all incoming and outgoing prisoners at S-21. The Witness provides details
concerning the location, structure, hierarchy and operation of S-21, and describes in detail the internal functioning of the Documentation Unit. He testifies to the composition of prisoners, which included Cambodians, Europeans, Americans, Vietnamese civilians and prisoners of war, women and children, CPK senior cadres (including Ta Nat and Vorn Vet) and former S-21 staff.
He describes the conditions within the prison, and testifies that many prisoners died from disease and insufficient nutrition. He also confirms that interrogations, torture and executions took place outside of the S-21 main compound, and that prisoners were transported to their executions in covered trucks. He testifies to the practice of blood drawing at S-21.