PHNOM PENH: Cambodia's war crimes court this week hears final arguments in the trial of the Khmer Rouge prison chief, with Duch expected to apologise for the regime's horrors in a bid to lessen his sentence.
Duch, 67, has repeatedly used the UN-backed court since hearings started in February to publicly ask forgiveness for overseeing the murders of around 15,000 people at the Tuol Sleng torture centre three decades ago.
The former maths teacher is one of five leaders of the brutal communist movement who have been detained by the court but is the only one to have admitted any guilt on charges of crimes against humanity and war crimes.
A verdict in the trial, the first by the tribunal, is not expected until early 2010.
Duch - whose real name is Kaing Guek Eav - faces a life sentence in prison because the court cannot impose the death penalty.
"This will be a very meaningful and significant week for the people of Cambodia and the victims of the Khmer Rouge regime who lost their loved ones," tribunal spokesman Reach Sambath told AFP.
"They have waited for so long. Finally peace will be coming close to them."
The Khmer Rouge, led by "Brother Number One" Pol Pot, emptied Cambodia's cities during its 1975-1979 rule, exiling millions to vast collective farms in a bid to take society back to "Year Zero" and forge a Marxist utopia.
Up to two million people were executed in the notorious "Killing Fields" or died from starvation and overwork before a Vietnamese-backed force toppled the regime.
Pol Pot died in 1998. The Khmer Rouge court was established in 2006 after nearly a decade of negotiations between the government and UN, and many more years of civil war in Cambodia following the fall of the regime.
Arguments this week are expected to be shown live on television across Cambodia, and the court said that thousands of people have inquired about coming to the tribunal to watch from behind bullet-proof glass.
Prosecutors have tried to portray Duch, who was captured in 1999, as a meticulous executioner who built up a huge archive of photos, confessions and other evidence documenting inmates' final terrible months.
But the trial's format has allowed Duch to comment on all testimony and repeatedly give his own version, portraying himself as a terrified bureaucrat who performed his duty out of fear leaders would kill him and his family.
"I tried to survive on a daily basis, and that's what happened. And yes, you can say I am a cowardly person," Duch told the court in September.
Duch, a born-again Christian, has rejected several allegations he personally tortured and executed prisoners, and also denied prosecution assertions he played a key role in the Khmer Rouge leadership.
"The civil law system gave Duch far more time speaking out loud in the court than any other player.
That gave him a huge advantage over any of the other parties," said Heather Ryan, who monitors the court for the Open Society Justice Initiative.
His defence has indicated it hopes his contrite testimony will earn him a reduced sentence, pointing to a similar defence used by Hitler's main architect, Albert Speer, at the Nuremberg trials after World War II.
The tribunal itself has meanwhile faced continued controversy during the trial. There have been claims that Cambodian staff paid kickbacks for their jobs, while Prime Minister Hun Sen has opposed pursuing more suspects on the grounds that it could destabilise the country.
The court has also been hit by the early departure of prosecutor Robert Petit, who cited family reasons for resigning in July, and claims investigating judge Marcel Lemonde prefers evidence biased against accused leaders.
The other Khmer Rouge members awaiting trial are "Brother Number Two" Nuon Chea, former head of state Khieu Samphan, ex-foreign minister Ieng Sary and his wife Ieng Thirith, who was the minister of social affairs.
Most Cambodians have welcomed the idea that Duch at least partially confessed in the court, which is seen as the last hope to deal with Khmer Rouge crimes - but few are ready to forgive his past.
"Duch is like a piece of white paper - when it is stained with black ink, it cannot be totally cleaned," said Bou Meng, who is one of the handful who survived Tuol Sleng because his artistic skill was deemed useful to the regime.