Witness Suos Thy, a former list-maker at the infamous S-21 prison, testified before the Khmer Rouge tribunal yesterday, recounting the internal operations of the security centre.

He joined the Khmer Rouge rebels in 1971 during their struggle to overthrow the US-backed Lon Nol regime. In 1972 he fought in Siem Reap as a part of Regiment 123.

“I was wounded and then I was re-assigned as a medic,” he told the court.

Reassigned to Battalion 112, chaired by Huy, he maintained a list of personnel, weapons and ammunition and made daily reports to the regiment “until the day Phnom Penh fell in April 1975”.

Huy recommended Thy for his list-making skills to work under comrade “Hor” at PJ prison – the one-time judicial police station that later became an office of S-21 – before moving to the main compound at Tuol Sleng, where he remained until the Vietnamese-led invasion captured Phnom Penh in 1979.

“Hor was my superior in my guard unit and he received direct orders or instruction from Duch”, the chairman of S-21, Thy said, adding that “only Hor gave orders to me”.

Duch, whose real name is Kaing Guek Eav and who was convicted by the tribunal for his role in Case 001, is set to testify next week.

Despite his years of work at the prison and attending three-day political study sessions led by Duch, Thy said he did “not know about the objective or role of S-21 or that of the regime”.

In the afternoon, Thy said that, in his experience, “not a single prisoner was released”.“Duch was the one who made the decision as to the number of prisoners to be taken out for execution, and he was the sole decision-maker in this regard,” he said, adding that he prepared the execution lists based on notations made by Duch on prisoner’s files.

“He would annotate with the word kom, denoting the word komtech, or smash,” he said.

Describing prisoner intake, Thy said that “for the prisoner’s biography, I already had the preprinted form and I only needed to fill in the blanks”.

Children under the age of 15 were not recorded.

“Usually the children who came to that centre were with their parents,” he continued, adding that he could not remember if he registered children that arrived alone, although prosecutor Vincent De Wilde noted several in the files, including one accused of being a Vietnamese spy who was executed the day after being admitted.

Children were separated when it came time to smash them. “It was Hor who decided when to take out the children.”