Controversial footage filmed by Vietnamese troops after the Khmer Rouge fled the capital will not be permitted as evidence.

JUDGES at Cambodia's war crimes court on Wednesday decided against allowing the use of footage of Tuol Sleng prison shot by Vietnamese troops in 1979 as evidence in the trial of the prison's former chief, Kaing Guek Eav, citing time restrictions and concerns that the footage would be repetitive.

Defence lawyers for the accused had previously argued that the authenticity of the footage, which was donated in December by the Vietnamese government, has never been verified.

Prosecutors have said they believe the footage, which shows infants and children in poor health being removed from the compound, is necessary to demonstrate inhumane conditions at Tuol Sleng.

"It is undisputed that the conditions of detention at S-21 were inhumane," judges said in a filing Wednesday.

"The footage is likely to have little impact upon the trial and is in substance repetitious as a means of establishing these facts."

Judges added that "a number of supplementary investigations" would be necessary to prove the credibility of the footage.

"The chamber considers that verification of the reliability of this footage, a precondition for its use as evidence, is unlikely to be obtained within a reasonable time," they said.

Footage 'superfluous'

The footage is purported to show the prison immediately after it was discovered by Vietnamese forces.

Prosecutors had hoped to use the footage to prove that children had been detained with their parents, but judges said the testimony of a man who claimed to be one of the boys in the footage provided sufficient evidence of this.

"In view of the testimony of [child survivor Norng Chan Phal] and other witnesses ... this footage is superfluous to establish that children of arrested cadre were also brought to S-21," the judges said.

Defence lawyer Kar Savuth told the Post Wednesday that he believed the court had made the right decision.

"The reason I do not want to use this video [in the trial] is because most parts of it have been invented," he said. "The trial should be based on real facts, not invented ones."

Spencer Cryder, a legal associate for the Documentation Center of Cambodia, which first obtained the archival footage, said Wednesday that the decision reflected the general tendency of tribunal judges to resist supplementary investigations.

"The trial chamber's decision on the S-21 video did not address the root issue - the investigative inertia that exists during the [tribunal's] trial phase," he said.

"Only the trial chamber can order additional investigations during the trial phase. However, the chamber did not order such an investigation."