The defence team for Nuon Chea has called for investigative action in requesting documents from expert witness Alexander Hinton, saying his comments before the Khmer Rouge tribunal may have been “unfounded or simply incorrect”.

Alexander Hinton, academic and author of Why Did They Kill? testified for four days in mid-March on his theory of “ideological genocide” in the Cambodian context, as well as the “manufacturing of difference” to allegedly target groups like the Vietnamese and Cham.

It was his testimony that roused Nuon Chea from his holding cell to challenge Hinton’s conviction that the term yuon – a term for the Vietnamese often considered derogatory – incited violence.

According to a letter filed by the defence team to the court, the expert witness failed to deliver specific information about his interview sources, and therefore they were unable to ascertain the truth of his claims.

“There is absolutely no information regarding the authenticity and reliability of Mr Hinton’s evidence. In fact, as of now, there is simply no evidence that Mr Hinton actually conducted field research in Cambodia or interviewed any individuals, other than his own statements,” the letter read.

If the trial chamber was unable to assess the value of the expert witness report, it should not be admitted into evidence or only given “limited weight, if any”, the letter stated.

Defence lawyer Victor Koppe yesterday said that testing evidence was crucial to ensure his client’s right to a fair trial.

“We have doubts as to what he claims people said, so that’s why we’re asking for this,” Koppe said.