For almost 11/2 years, Kang Khek Iev, better known as Duch, has stood nearly motionless in the dock. His eyes, wide and vacant, betrayed little of the man on trial for the torture and deaths of thousands.
Throughout Case 001 of Cambodia's UN-backed war crimes court, Duch has apologised routinely for the horrors inflicted at the notorious S21 prison that he ran for the Khmer Rouge in the late 1970s. These included disembowelment, operations being performed without anaesthetic, and blood being drained from prisoners for use in transfusions. Children were taken from their mothers, fingernails were torn out, prisoners were left chained to corpses for days in the tropical heat. Meals were rare, beatings were common.
However, the 16,000 people who perished at the abandoned high school in suburban Tuol Sleng and in the Killing Fields on the outskirts of Phnom Penh represent a tiny fraction of the two million who were murdered or died of starvation and illness under Pol Pot and his ultra-Maoist regime from 1975 to 1979.
What set the victims of S21 apart from the brutality afflicting the rest of the country was the disciplined, calculating - and well documented - methods by which they were killed. Duch, 67, will hear the verdict in his case tomorrow.
Eminent Cambodia scholar David Chandler said Duch - a former maths teacher - differed on two counts from other senior Khmer Rouge leaders of the day. 'He was very intelligent and he has apologised. He's interesting to that extent,' the American told the South China Morning Post.
It's a point taken up by Rob Hamill, a New Zealander whose brother Kerry was captured by the Khmer Rouge and among a handful of Westerners who died at S21. 'He effectively ran the secret police. He developed the system. He was the mathematical genius who created the killing machine that the rest of the country followed,' Hamill said.