Former Khmer Rouge head of state Khieu Samphan pledged yesterday to help Cambodia’s war crimes tribunal discover “the truth” about Democratic Kampuchea and his role within the regime.

The promise came during a morning session at the court yesterday focused on proposed witness lists in the trial of Khieu Samphan, former KR Brother Number 2 Nuon Chea, social action minister Ieng Thirith and her husband, foreign minister Ieng Sary.

Khieu Samphan told the court he would help it “ascertain the truth”, though he added that such truth would only come out if the court agreed to hear witnesses on his behalf.

“I think it is a very important moment for me and for my fellow Cambodian citizens who are hungry to understand what happened between 1975 and 1979. I personally have been waiting for this moment for so long,” the 79-year-old said. “As long as I am still as healthy as I am today, I will contribute to the best of my ability, of course from the bottom of my heart, to assist or cooperate with the work of the court.”

Khieu Samphan complained, however, that most of the witnesses approved by the Trial Chamber judges thus far have been identified by the prosecution rather than the defence teams.

“Many of the witnesses that I proposed have known me very well – they have been close to me, they know where I would be doing anything, and of course they have a very good account of me,” he said.

“I would really request that the chamber take note and include those witnesses and summon them for testimony. They shall be heard – I don’t say they should, but they shall be heard.

“Some witnesses of course actually do not really tell the true story, or sometimes they just exaggerate the information. That’s why it is really important that our witnesses be included.”

Khieu Samphan has previously claimed that he did not have any real power during the Democratic Kampuchea period and was not responsible for any atrocities committed.

The witness list under discussion yesterday covered only individuals tapped to testify during the first phase of the trial, and additional proposed witnesses may be considered as the case progresses.

Earlier in the hearing, the defence team for Nuon Chea earned a rebuke from the judges after complaining about the alleged unfairness of the investigation and revealing the identity of one of their proposed witnesses. The judges had instructed the parties to refer to witnesses only by coded pseudonyms to protect them ahead of their potential appearance in court.

Dutch defence lawyer Victor Koppe charged that the court’s investigating judges had refused to interview witnesses who could benefit Nuon Chea’s case, and in particular the former cadre’s claims in relation to the role of Vietnam during the DK period.

“Our client instructed us that it was very important to investigate the role of Vietnam, not only in the period of 75-79, but also in the time before and after the period of Democratic Kampuchea,” Koppe said.

“Many decisions in the DK period were taken because of Vietnamese policy, and such decisions can only be properly understood if Vietnam’s role and policy is thoroughly investigated.”

As an example of one proposed witness on the issue whom the investigating judges had declined to interview, Koppe cited a man whom he referred to as “Mr X”, later providing biographical details that clearly revealed the individual as Pen Sovan, the former prime minister of the Vietnamese-backed People’s Republic of Kampuchea.

“Our client was of the opinion that the testimony of Mr X is very, very important for ascertaining the truth – very important to understand the role of Vietnam,” Koppe said.

Deputy prosecutor William Smith cut Koppe off during his remarks, however, saying it was “not appropriate to call someone Mr X and then start to bring out every detail that would identify Mr X”.

Koppe went on to criticise the quality of the investigation in the case, prompting Smith to interrupt him once again.

“You will lose control of this trial if people are allowed to make speeches and not confine themselves to the agenda that you set,” Smith advised the judges.

Pen Sovan told The Post last June that he had yet to be summoned as a witness, but that it would be his “honour” to give evidence at the court.

During the first day of the trial on Monday, Nuon Chea walked out in protest, saying he was “not happy” with the proceedings. His lawyers later explained that he did not wish to be present in the courtroom “unless his objections and all of his witnesses ... are put on the agenda”.

Defence lawyers have called for the testimony of King Father Norodom Sihanouk and six senior government officials including National Assembly President Heng Samrin and Senate President Chea Sim, all of whom have apparently ignored summonses issued by the tribunal. Nuon Chea’s lawyers have also called for witnesses in relation to the roles of Vietnam and the United States in the DK period.

Nuon Chea excused himself   early from hearings on Tuesday and Wednesday because his own case was not on the agenda. Koppe said following the hearing yesterday that his client was likely upset his lawyers had been cut off, and that the team was considering whether it would be “fruitful” for him to participate in the trial in the future.

“I would say that if we continue like this – an initial hearing … where an agenda is set and where there’s no room to have a proper debate –  then there might come a point in time that there seems to be no point for him to be present,” Koppe said.

Others were more sanguine. Co-prosecutor Andrew Cayley said it had been “an extremely positive week”, and that the court was “in a place where a lot of people said we never would be”.

“A lot of people said this trial would never happen, and actually, it’s going to trial and it appears, from what we’ve seen of the recent hearing, and also the accused and their level of cooperation, that it’s more than many, many people could have hoped for,” he said.