It's six years now since the UN–backed Cambodia tribunal was established to bring to trial senior leaders and those most responsible for genocide and war crimes committed during the Khmer rouge regime which lasted from 1975 to 1979.

During that period an estimated 1.7 million people are believed to have died from starvation, torture, execution and forced labour.

To date, only one person has been convicted by the tribunal. Kaing Guek Eav, alias Duch, who served as chairman of Phnom Penh’s security prison, was sentenced to 35 years imprisonment but which was later increased to life imprisonment.

The tribunal is expected to deliver its verdict on the trial of three other former leaders sometime in 2014.

Nicholas Koumijian is the International Co-Prosecutor at the Cambodia tribunal. UN Radio’s Patrick Maigua asked him why the number of those on trial has been so small.

Duration: 6'04"