Defense lawyers for the jailed Khmer Rouge prison chief Duch have asked that the UN-backed tribunal post on its Web site documents prepared by a US researcher.

Craig Etcheson, a Khmer Rouge expert and author of “The Rise and Demise of Democratic Kampuchea,” is employed by the prosecution section of the tribunal and is the first foreign expert to testify at Duch’s trial.

Etcheson collected information related to Tuol Sleng, the prison run by Duch, including testimony about former Khmer Rouge cadre from different zones and ministries.

Duch, 66, whose real name is Kaing Kek Iev, is facing a battery of atrocity charges for his role as director of Tuol Sleng, a former high school, known to the Khmer Rouge as S-21.

During his testimony on Tuesday, Etcheson described widespread purges of the Khmer Rouge’s own government and military officials.

Tuol Sleng at one time held 532 people from the Public Works Ministry, or 15 percent of its workforce, 386 officials from the Commerce Ministry, 286 from the Energy Ministry and 251 from the Railway Ministry, Etcheson told the court.

Defense lawyer Francois Roux told judges Wednesday the research provided by Etcheson should be posted on the tribunal’s Web site “as quickly as possible” to help Cambodians understand the regime.

Questions over the documents took up the entire hearing Wednesday, as Duch remained silent throughout .