The three defendant on trial in Cambodia before the Extraordinary Chamber in the Courts of Cambodia, a UN-backed Tribunal , Nuon Chea, 85, Kieu Samphan,78, and Ieng Sary, 86, deny charges of genocide, crimes against humanity and war crimes for their alleged roles in the deaths of up to 2.2 million people the Khmer Rouge four-year-rule from 1975 to 1979.

On November 17, the tribunal revealed that Ieng Thirith, the former social affairs minister, who was expected to be the fourth defendant, was unfit for trial because of dementia.

The trial opened on Monday and despite the accused's denial, the opening statements provided detailed "a system of brutality that defies belief to the present day."

Between 1.4 and 2.2 million people died of execution, starvation, exhaustion or lack of medical care during the Khmer rouge regime after the party's hard-line policies turned Cambodia into a forced labour camp as the movement attempted to create a pure agrarian socialist society.

Following are more information about the three defendants