The international court convened in Cambodia to judge the Khmer Rouge for its brutal 1970s rule ended its work Thursday after spending $337 million and 16 years to convict just three men of crimes after the regime caused the deaths of an estimated 1.7 million people.

In its final session, the U.N.-assisted tribunal rejected an appeal by Khieu Samphan, the last surviving leader of the Khmer Rouge government that ruled Cambodia from 1975-79. It reaffirmed the life sentence he received after being convicted in 2018 of genocide, crimes against humanity and war crimes.

Busloads of ordinary Cambodians turned up to watch the final proceedings of a tribunal that had sought to bring justice, accountability and explanations for the crimes. Many of those attending Thursday’s session lived through the Khmer Rouge terror, including survivors Bou Meng and Chum Mey, who had given evidence at the tribunal over the years.

Khieu Samphan, sitting in a wheelchair and wearing a white windbreaker and a face mask, listened to the proceedings on headphones.

He was the group’s nominal head of state but, in his trial defense, denied having real decision-making powers when the Khmer Rouge carried out a reign of terror to establish a utopian agrarian society, causing Cambodians’ deaths from execution, starvation and inadequate medical care. It was ousted from power in 1979 by an invasion from neighboring communist state Vietnam.