A request by Ao An’s defence team to annul investigations and charges stemming from the Tuol Beng execution site ultimately fell flat at the Khmer Rouge tribunal due to a disagreement between international and national pre-trial judges, according to a court document made public last week.

The redacted document, which is addressed to An’s lawyers and names him on one occasion, calls for crimes against humanity and premeditated murder charges related to Tuol Beng to be dropped, and for the investigation into the Wat Angkuonh Dei crime site to be annulled. Ao An stands accused of several other crimes against humanity at other sites, including genocide.

But, following a pattern of marked division between Cambodian legal teams and their international counterparts at the court, the judges were not able to reach the four votes needed to have those charges dismissed.

While the three national pre-trial judges – Prak Kimsan, Ney Thol and Huot Vuthy – agreed the investigations into those sites “must be annulled” because Ao An was not a senior leader or one of those most responsible for the crimes of the regime, their international counterparts Olivier Beauvallet and Kang Jin Baik maintained those zones fell “squarely within the scope of the judicial investigation”.

An’s defence had claimed certain sites were not included in the scope and were thus “procedurally defective”.

In the document, international prosecutor Nicholas Koumjian urged the judges to dismiss An’s request, saying that An’s right to a fair trial had not been breached, and that “even if existence of procedural defect and harm were established, under the circumstances of this case, annulment would be a drastic and disproportionate remedy”.