The role of the Co-Prosecutors is to prosecute senior leaders of the Khmer Rouge and others most responsible for crimes committed during the period of Democratic Kampuchea (from 17 April 1975 to 7 January 1979). To this end, the Office of the Co-Prosecutors (OCP) conducts preliminary investigations, participates in judicial investigations and prosecutes the accused at trial and on appeal. The OCP is the only office of the ECCC that participates in every step of the process, simultaneously across all cases. In every phase, the Co-Prosecutors are committed to ensuring that suspects, charged persons and the accused are subject to a fair trial, in accordance with international standards.
The OCP is an independent office that carries out its duties free from any interference, governmental or otherwise. Led by National Co-Prosecutor Ms. Chea Leang and International Co-Prosecutor Mr. Nicholas Koumjian, the office is comprised of both national and international staff and interns. As of February 2017, 27 staff members work as prosecutors, legal officers, translators, information managers and administrative assistants in the OCP. The office also relies heavily upon the significant contribution of up to 20 young professionals working as interns and consultants at any one time.