"This trial is important for Cambodia, but not just Cambodia it is important for the entire world," she said. "It demonstrates that crimes of such magnitude and severity will not be forgotten and that those responsible will be held to account."
While Khieu Samphan sat in the courtroom Thursday, often closing his eyes, Nuon Chea followed the proceedings by a video link from a holding cell due to ill health.
Their trial began in November 2011. To make a massive indictment more manageable, the judges split the case into a series of smaller trials that would examine evidence in rough chronological order. The present trial's focus on the forced movement of people excludes some of the gravest charges related to genocide and detention centers.
Many fear further trials will never take place, given the slow pace of the proceedings and the poor health of the aging defendants. The trial already has lost two other defendants to death and dementia.
Chea Leang said she hoped the examination of the forced evacuation of the capital, Phnom Penh, would offer a foundation for understanding "one of the most factually complex criminal cases ever prosecuted."
"From the moment that the residents of Phnom Penh left their homes and embarked into the unknown, they were the virtual slaves of the Khmer Rouge soldiers who escorted them," she said.
The entire population, including young children, pregnant women, the elderly and even hospital patients were "exposed to the elements at the hottest month of the year without water, shelter, food or medical assistance," she said. "Those who could not leave and had no relatives to help them were abandoned to die."
The U.N.-assisted court, launched in 2006, so far has convicted only one defendant, Khmer Rouge prison director Kaing Guek Eav, who was sentenced to life imprisonment in 2011. Cambodia has no death penalty.