The most senior Khmer Rouge official yet to face charges has been jailed for life.
Duch, formerly known as Kaing Guek Eav was found guilty of crimes against humanity and jailed in 2010 for 35 years.
He appealed the decision, claiming he was a junior official following orders and would have been killed if he didn’t obey the commands.
However his appeal was rejected and judges increased his sentence to a life term.
The appeal court judges held that the initial sentence of 35 years did not "reflect the gravity of the crimes".
"The crimes by Kaing Guek Eav were undoubtedly among the worst in recorded human history. They deserve the highest penalty available," Judge Kong Srim said.
Duch was in charge of the notorious Tuol Sleng prison, where over 15,000 men, women and children, who were accused of being enemies of the Khmer Rouge, were tortured and executed.
Over 2 million people are thought to have died during the Khmer Rouge regime’s brutal reign in Cambodia.
