[JURIST] The United Nations (UN) [official website] on Wednesday refused to replace a judge presiding over investigations at the Extraordinary Chambers in the Courts of Cambodia (ECCC) [official website] after Cambodia attempted to block him. Laurent Kasper-Ansermet is the judge tasked with investigating two possible suspects believed to be involved in the deaths of around 1.7 million people during the reign of the Khmer Rouge [BBC backgrounder] regime. The investigation relates to ECCC cases 003 and 004 [materials]. The Cambodian government strongly opposes the investigation into the suspects’ involvement with the Khmer Rouge. Cambodia attempted to block Kasper-Ansermet’s return to the country under an agreement between the UN and the Cambodian government. Cambodian officials said they believe they have the authority to reject investigating judges they deem unsuitable. Cambodia says Kasper-Ansermet is unsuitable to continue the investigation [Reuters report] because he used his Twitter account to comment on the cases. According to the UN, the agreement between the Cambodian government and the UN gives “full authority to operate as the international investigating judge.”

Last week, the UN expressed concern [JURIST report] over Cambodia’s decision to not appoint the reserve judge Kasper-Ansermet to the ECCC after the previous judge, Siegfried Blunk, resigned [JURIST report] in October. ECCC judges, including Blunk, have been criticized for allegedly failing to conduct impartial investigations. Cambodia has argued that the trial of former Khmer Rouge leaders is a Cambodian issue and should not be a matter of international concern. Also in October, defense lawyers for accused Khmer Rouge leader Nuon Chea filed a lawsuit [JURIST report] against Cambodian Prime Minister Hun Sen [BBC profile] for interfering with the UN-backed war crimes tribunal. Nuon’s lawyers accused the prime minister of criminally conspiring to block some of the defense witnesses from testifying [Reuters report] and consequently interfering with his right to a fair trial. In September, the ECCC ordered the trials be split into a series of smaller trials [JURIST report].