Prime Minister Hun Sen used the first visit of a new UN human rights envoy to raise allegations from Khmer Rouge torture chief Duch that a UN rights officer offered to help him leave the country.

Duch, who is undergoing an atrocity crimes trial at the UN-backed tribunal, has said in testimony he was once approached by Christopher Peschoux to be helped out of the country. Duch said he refused to leave.

Peschoux, who was once a rights monitor in Cambodia and is now head of the country’s UN rights office, could not be reached for comment, but former colleagues say he is an expert in international law and was unlikely to have made such an offer if he knew who Duch was.

Hun Sen pressed UN special envoy for human rights to Cambodia, Surya Subedi, on the allegations, questioning whether such behavior fit the role of the head of the country’s human rights office, according to a spokesman for the premier, Eang Sophallet.

Hun Sen requested that Subedi work with Cambodia’s chief human rights official, Om Yentieng, to look into the allegations.

A former staff member for Peschoux, who spoke on condition of anonymity, said Duch might have the wrong person or may be misremembering, “we do not know.”

Like other alleged war criminals, Duch would be unlikely to find refuge in another country, the former staff member said.