Re-education was not the point: Duch.

TO DESCRIBE the Prey Sar prison farm as a Khmer Rouge re-education centre would be misleading, as most detainees sent there during the regime had no hope of being released, Tuol Sleng prison chief Kaing Guek Eav told Cambodia's war crimes court Wednesday.

"In practice, re-education aimed towards the final stage, which was to smash," said Kaing Guek Eav, alias Duch, who was in charge of Prey Sar, or S-24, during his tenure as head of Tuol Sleng.

The detainee population consisted of Khmer Rouge cadre from in and around Phnom Penh who had committed minor offences that were not seen as grounds for immediate execution, Duch said.

He said only 30 detainees were ever released, as nearly all were sent either to Tuol Sleng or the Choeung Ek killing fields.

Detainees worked for at least eight hours each day, mostly producing rice. Presiding Judge Nil Nonn cited evidence that detainees were subjected to interrogation, beatings and electrocution, though Duch said any torture at the facility was done "without my authorisation", perhaps at the behest of Nun Huy, who ran it.

Duch said he visited the facility only four times and routinely cited surviving documents rather than firsthand observations when describing its operations. He said he could not estimate how many detainees passed through the facility.

Youk Chhang, director of the Documentation Centre of Cambodia, said Wednesday that there were "not proper documents to identify the number of detainees at S-24".