Attempts by the prosecution to glean information about Mondulkiri’s Phnom Kraol security centre were frustrated by an uncooperative witness who frequently claimed ignorance, often contradicting his prior statements, as well as the previous testimony of his brother.

Witness Sao Maing, who was tasked with guarding the border area in O’Raing district near Dak Dam commune, was in command of 100 soldiers in Regiment 2 from 1976 to 1979.

While the witness did testify that the sector secretary, Laing, was in charge of Phnom Kraol prison, he refused to corroborate a previous statement in which he said “Laing had subordinate soldiers arrest people”.

“I did not know because it was not my business,” Maing said, a stance he repeated when pressed by the prosecution.

Khmer Rouge leaders Khieu Samphan and Nuon Chea are on trial for various crimes against humanity, including atrocities committed at centres like Phnom Kraol.

However, Maing remained firm when questioned by civil party lawyer Lor Chunthy, who asked about the conditions at the prison, the reasons prisoners were arrested and whether they were soldiers or civilians. Despite being a high-ranking officer in the area, he said he did not know.

Prosecutor Dale Lysak also asked the witness about the disappearance of his immediate supervisor, Leng, in 1978. Documents show Leng was executed at S-21.

The witness initially refused to even confirm that he knew of the disappearance of his own commander. “I did not know about those peoples’ affairs,” he said, contradicting a previous statement in which he had said Leng was called to “study” and never returned.

Lysak went on to ask who took over as head of the regiment after Leng’s disappearance.

“For me, it’s not my business,” Maing said, maintaining he did not know who replaced his direct superior.

In response, Lysak read a statement from Maing’s brother, Sarun, who himself eventually replaced Laing as sector secretary. Maing, Sarun told investigators in 2008, also moved up the ranks to replace his disappeared superior, Leng.

“No, I did not do that,” Maing said in response.

“You confirmed earlier this morning that it was the sector secretary who made appointments . . . The sector secretary at the time Leng was arrested was your brother,” Lysak said.

Again, Maing held fast: “I do not know.”