Pol Pot's chief torturer took the stand on Monday, charged with crimes against humanity in the first trial of a top Khmer Rouge cadre 30 years after the end of a regime blamed for 1.7 million deaths in Cambodia.
Duch, former chief of the notorious S-21 prison where more than 14,000 enemies of the ultra-Maoist revolution died, stood before a five-judge panel and calmly answered questions about his background.
I have been notified of the charges against me, the 66-year-old former maths teacher told the joint U.N.-Cambodian tribunal as hundreds of onlookers watched from a public gallery.
Prosecutors began laying out their case against Duch, accusing him of crimes against humanity, enslavement, torture, sexual abuses and other inhumane acts while head of S-21, also known as Tuol Sleng and now a museum.
Duch, whose real name is Kaing Guek Eav, is expected to enter a plea later this week. If found guilty in a verdict expected in September, he could face a maximum of life in prison in Cambodia, which has no death penalty.
The born-again Christian has expressed remorse for the S-21 victims, most of them tortured and forced to confess to spying and other crimes before they were bludgeoned to death in the Killing Fields outside the Cambodian capital Phnom Penh.
The prosecutors' statement read out in court on Monday said Duch often watched people being tortured and later murdered.
It cited unnamed witnesses who described medics taking blood from prisoners to be used later by Khmer Rouge cadres. Witness E said no fewer than a thousand persons were killed in this manner.
Other witnesses said children were taken away from their parents, who were jailed at S-21 and killed.
Children were dropped from the third floor of the (S-21) complex in order to break their necks, the statement said.
During questioning by court investigators before his trial, Duch said he was just following orders. That angered Om Chantha, 69, whose husband, a doctor, was killed by the Khmer Rouge.
Duch killed thousands of people, but he showed no regret. I just don't understand, she said during a break in the trial.
The trial, held in a specially built court on the outskirts of Phnom Penh, marks a turning-point for the strife-torn country, where nearly every family lost someone during Pol Pot's Year Zero revolution to achieve an agrarian utopia.
Duch is expected to be a key witness in the future trials of those also deemed most responsible for one of the darkest chapters in the 20th century.
The other four -- Brother Number Two Nuon Chea, the regime's ex-president, Khieu Samphan, and Ieng Sary, its foreign minister, and his wife -- have denied knowledge of any atrocities.
Advocates hope the tribunal -- formally known as the Extraordinary Chambers in the Courts of Cambodia (ECCC) -- will serve as a model of professionalism for the country's erratic and politicised judiciary.
Critics say the tribunal's integrity is threatened by allegations of corruption and political interference, particularly on the issue of pursuing other Khmer Rouge suspects.
A bid to go after more suspects was brushed aside in January by the tribunal's Cambodian co-prosecutor, who said it would not help national reconciliation. The government has denied meddling in the court, but rights groups are concerned.
The Extraordinary Chambers must urgently expand its prosecution strategy to investigate and prosecute more cases before it is too late, said Brittis Edman, a Cambodia researcher for rights group Amnesty International.
(Writing by Darren Schuettler; Editing by Alan Raybould and Sugita Katyal)