The story

Kaing Guek Eav is an elderly former math teacher and a born-again Christian.

He is also -- prosecutors contend -- a former prison chief with Cambodia's Khmer Rouge movement who oversaw the torture and killing of more than 15,000 men, women and children three decades ago.

The trial of the 66-year-old man, better known as Duch, began Monday in front of a U.N.-backed tribunal just outside the Cambodian capital, Phnom Penh. Read full article »

CNN's Dan Rivers and Miranda Leitsinger contributed to this report.

All About Cambodia • Khmer Rouge • War Crimes • Genocide