Jailed Khmer Rouge prison chief Duch, who earlier this week toured by the Choeung Ek "killing fields" and Tuol Sleng prison, was confronted by witnesses against him at the tribunal chambers Thursday, in a further sign that proceedings against him were moving forward.

"This is a very important step," said Helen Jarvis, a tribunal spokeswoman. "The last two days, we held the reconstructions and onsite investigations, and today and tomorrow we move to the confrontation interview."

After the confrontation interviews, the investigating judges will conclude the judicial investigation and forward decisions to prosecutors, she said. "And then after that, we will be able to move to the trial phase."

Duch, who is charged with crimes against humanity, spent Tuesday and Wednesday undertaking reconstructions with witnesses and judges and others at Choeung Ek and Tuol Sleng.

Youk Chhang, director of the Documentation Center of Cambodia, said he hoped the proceedings so far were pertinent to Duch's upcoming trial.

"If not, we have lost more time," he said.