Most of the victims of the 1975-79 regime died of starvation, torture, exhaustion or disease in labor camps or were bludgeoned to death during mass executions.
Between 1.7 and 2.2 million people, almost a quarter of the population, died during the 1975 to 1979 rule of the Khmer Rouge.
The Extraordinary Chambers in the Courts of Cambodia (ECCC), said Khmer Rouge "Brother Number Two", Nuon Chea, 92, and former President Khieu Samphan, 87, were guilty of genocide against the Cham Muslim minority and Vietnamese people, and of various crimes against humanity.