Under Khmer Rouge rule, from 1975 to 1979, Cambodia’s urban population was forcibly moved into the countryside as part of enforcing agricultural reform policies. Many died from exhaustion, disease or starvation. Many were tortured and executed. The total death toll during the Khmer Rouge regime is reported to have been at least 1.7 million. Violent deaths are believed to account for about 50% of this figure.

The independent Documentation Center of Cambodia, set up in 1994 after the return to multiparty democracy, has identified 19,733 mass graves spread over 388 sites. These graves are believed to contain the bodies of over 1.1 million people.

In 1989, the Cambodian Red Cross began helping Cambodians to trace missing family members. By 2000, tracing requests for more than 20,000 people had been collected.

The Documentation Center of Cambodia aims to create a comprehensive list of all missing persons by the end of 2014.

In 2001 special UN-backed courts were established to bring Khmer Rouge officials to justice. In 2012, Kain Guek Eav, known as Comrade Duch, became the first person to be convicted before the Extraordinary Chambers in the Courts of Cambodia (ECCC). In August 2014 two former leaders of the Khmer Rouge were found guilty and sentenced to life imprisonment.

The Cambodian Tribunal Monitor and the German-based Civil Peace Service (CPS) work to aid the reconciliation process by ensuring that Cambodian citizens are informed about ECCC proceedings and outcomes.