TUOL SLENG, Cambodia (CNN)  -- The trial of a former prison chief with the Khmer Rouge movement resumed inside a packed Cambodian courtroom Monday, with prosecutors painting a grim picture of inmates who were electrocuted, whipped and beaten to death. Duch ran a prison where people were tortured and killed under the Khmer Rouge. Kaing Guek Eav, a former math teacher and a born-again Christian, displayed no emotion as the U.N.-backed tribunal accused him not just of overseeing the torture and killing of more than 15,000 men, women and children three decades ago -- but of actively taking part in some of them.
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NEW: Duch offers basic introduction of himself; court officials read probe's findings
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Duch's trial is taking place outside the Cambodian capital, Phnom Penh
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Prison victims were military officials, Communist Party members
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Duch, former prison chief, has admitted role in Khmer Rouge's reign
The tribunal, which is made up of @placeholder and international judges, does not have the power to impose the death penalty.