Thousands of people died at the prison Duch ran at Tuol Sleng
Lawyers at the trial of the Khmer Rouge's former prison chief in Cambodia are making closing arguments, after months of testimony.
Kaing Guek Eav, better known as Comrade Duch, ran a prison where thousands of people were tortured and murdered in the late 1970s.
The 67-year-old is accused of crimes against humanity and faces a life sentence in prison if convicted.
He is the first of five top Khmer Rouge figures to face the UN-backed tribunal.
As many as two million people are believed to have died under the Khmer Rouge, the Maoist regime that controlled Cambodia from 1975 to 1979.
Duch went on trial in February, after years of wrangling over the establishment of the tribunal. A verdict in his case is expected early next year.
This week is the final chance for the prosecution and defence to have their say before the judges retire to consider their verdict.
WHO WERE THE KHMER ROUGE?
Maoist regime that ruled Cambodia from 1975-1979
Founded and led by Pol Pot, who died in 1998
Abolished religion, schools and currency in a bid to create agrarian utopia
Up to two million people thought to have died from starvation, overwork or execution
Time has also been set aside for lawyers representing dozens of people who lived through the Khmer Rouge era, including the only three confirmed survivors of the notorious S-21 prison.
Duch ran S-21, also known as Tuol Sleng. As many as 17,000 inmates are thought to have passed through the gates of that facility.
All but a handful were tortured, forced to "confess" to crimes against the regime and then put to death at the so-called killing fields just outside Phnom Penh.
Duch has admitted that he was in charge of S-21 and apologised in court for his part in the horrors committed there.
He has said he was only following orders because he feared for his life. He is expected to address the court later this week.
"At this moment it's very important to give credit to Duch for his guilty plea," his lawyer Francois Roux said on Sunday. "Duch has recognised his responsibility."
But lawyers for the victims told the court on Monday this was not enough.
"Even today, the accused has sought to evade or minimise his role and the awful reality that was S-21...and suffering that befell so many civil parties that we all represent," lawyer Karim Khan said.
Co-prosecutor Bill Smith said he believed the trial had helped Cambodians come to terms with their country's history.
"I think the trial has been very, very successful," he told the BBC.
"The fact that the court has allowed the victims to participate through their civil party lawyers has been a real major success, connecting what's happening in that courtroom back to the people who experienced the tragedy of S-21."
The trial of four other top Khmer Rouge leaders is expected to begin in 2011.