Cambodia's U.N.-backed tribunal on Thursday ruled a former senior Khmer Rouge leader unfit to stand trial for genocide and other crimes because she has Alzheimer's disease.
The tribunal said the illness diminishes Ieng Thirith's mental capacity and ordered the 79-year-old defendant freed from detention. She behaved erratically at earlier court appearances, and her lawyers had requested the medical exams.
Tribunal spokesman Lars Olsen said Ieng Thirith would be freed from the tribunal's detention facility within 24 hours of the ruling if prosecutors do not appeal.
The ruling came just four days before the start of her trial with three co-defendants, one of whom is her husband, Ieng Sary, foreign minister in the late 1970s Khmer Rouge regime. He informed the tribunal last month that he intends to exercise his right not to testify.
Ieng Thirith was minister for social affairs and is accused of involvement in the "planning, direction, coordination and ordering of widespread purges" and has been charged with crimes against humanity, genocide, homicide, torture and religious persecution.
The U.N.-backed tribunal is seeking justice for an estimated 1.7 million people who died of starvation, exhaustion, lack of medical care or execution during the communist Khmer Rouge's rule.
Ieng Thirith has said the charges against her are "100 percent false" and said she always worked for the benefit of the people.
She is the sister-in-law of Khmer Rouge supreme leader Pol Pot, who died in 1998. Pol Pot married Ieng Thirith's sister, Khieu Ponnary, who died in 2003.
The other defendants were also part of the ruling inner circle: head of state Khieu Samphan and Nuon Chea, who was second in command to Pol Pot and the group's chief ideologist. The three remaining defendants assert they are innocent.
The trial may be Cambodia's best chance to hold accountable the accused architects of the "killing fields" and the enslavement of millions of Cambodians.
They and Ieng Thirith formed what the tribunal calls Case 002. The chief Khmer Rouge jailer was convicted last year in the breakthrough Case 001.
Political and financial pressure on the tribunal has raised doubt if a Case 003 will ever exist.