"He is a ruthless man... The trial of Duch is the right thing to do. I myself tortured some prisoners, but if I didn't do it I would have been killed too."
These are the words of Prak Khan, 53, who researchers say drove inmates at Cambodia's notorious Tuol Sleng prison to be slaughtered at the nearby "killing fields" during the brutal Khmer Rouge regime of 1975-1979.
Three decades on, the prison's former boss Kaing Guek Eav, better known as Duch, will appear in court this week for the first trial of Cambodia's UN-backed Khmer Rouge tribunal.
The Khmer Rouge was ousted by Vietnam-backed troops in 1979 and now Tuol Sleng, a dilapidated collection of former school buildings, is a genocide museum which displays mug shots of doomed inmates.
Tuol Sleng guards as well as inmates are being confronted with alarming questions about how their experience fits into the history of the bloody regime.
Khieu Poe, a former Tuol Sleng guard, says he still has nightmares of being arrested and killed at the prison.
"We just followed orders. Under the regime we couldn't say anything. If we did, we would have problems ourselves," he says.
Backing that up, investigators estimate 200 Tuol Sleng staff became prisoners there, facing certain execution.
But that does not ease the memories of Bou Meng, who lost his wife at Tuol Sleng and only survived his time there because he was put to use painting portraits of "Brother Number One" Pol Pot.
"They treated me worse than an animal. They beat me up worse than a buffalo or cow. I was imprisoned for more than one year," Bou Meng says.
"For those guards, it is up to a court to judge them. I dare not decide about (their guilt)."
Chum Mey, another former prisoner at the secretive detention centre and one of only a handful to have survived the experience, says his Khmer Rouge torturers haven't changed.
"Inside their hearts and minds they're still Khmer Rouge, and on their lips they're just talking," he says.
Duch was arrested a decade ago when he was discovered working at a Christian aid agency in western Cambodia.
He has admitted to the atrocities committed under his command, and will answer the court's charges of war crimes, crimes against humanity, torture and premeditated murder.
However Tuol Sleng, also code named S-21, was merely the main killing apparatus among 198 Khmer Rouge torture centres throughout Cambodia.
Duch's trial is expected to raise questions about the chain of command within the regime, and how much the inner circle of Khmer Rouge leaders controlled their regime's killing apparatus.
"Many people accuse Duch of killing a lot of people at Tuol Sleng. I don't know if it was under orders or his own idea. If he didn't do it, he might have been killed as well," says Cheam Seur, who stood sentry outside the prison.
Pol Pot died in 1998, but the UN-backed court plans to prosecute other former Khmer Rouge leaders.
"Brother Number Two" Nuon Chea, former head of state Khieu Samphan, ex-foreign minister Ieng Sary and his wife Ieng Thirith, who was the social affairs minister, are all in jail waiting to answer for their alleged roles.
As Duch faces life in prison, Tuol Sleng's prisoners and guards alike hope his trial will help answer how the Khmer Rouge came to kill up to two million people through starvation, overwork, torture and execution in its attempt to forge a communist utopia.
"I want to ask him: 'I didn't do anything wrong, why was I brought here and tortured? Why was my wife wrong? Why were my children wrong? Millions of people were killed," Chum Mey says.
"We want to find the truth. They killed people -- we want to find out whether they did it by themselves or got orders to kill somebody."