For several years, Cambodian society had been stirred up by the possibility that those responsible for the Khmer Rouge genocide could be brought to trial. This is the context in which film-maker Rithy Panh undertook a film project based on confronting the memories of victims with those of their former torturers. For more than two years he conducted an investigation to find the people involved, and to persuade them to meet at Tuol Sleng, the torture centre in Phnom Penh where some of them were plunged into horrifying everyday reality, and others served the machinery of programmed dehumanisation and extermination.