A UN-backed tribunal in Cambodia on Friday rejected an appeal by Khmer Rouge prison chief Duch, ruling that he must spend the rest of his life in prison.
The 69-year-old was found guilty of murder, torture, rape and crimes against humanity in July 2010 and sentenced to 35 years in jail
The former school teacher argued in his appeal that the court had no jurisdiction to try him because he was not a top Khmer Rouge commander.
Judges rejected that claim and extended his initial jail term to life.
He ran the S-21 jail in Phnom Penh where at least 14,000 people were killed.
Nearly two million died between 1975 and 1979 in Pol Pot’s genocidal pursuit of a Maoist utopia.
His regime abolished money, private property and forced people to work on farms, whilst purging any opponents or so-called enemies of the state.
Pol Pot died in 1998 before he could be brought to justice.