Survivors of the Cambodian genocide are shocked that one of the leaders of the former Khmer Rouge regime will be set free after a court in Cambodia ruled that she was medically unfit to stand trial.

Cambodia’s UN-backed tribunal issued a statement on Thursday saying that 80-year-old Ieng Thirith suffers from a progressive, degenerative illness, probably Alzheimer’s disease, and that diminishes her mental capacity.

“There is no prospect that the accused can be tried in the foreseeable future,” the tribunal said.

“Experts have confirmed that all treatment options have now been exhausted and that the accused’s cognitive impairment is likely irreversible.”

She is “unfit to stand trial”, the statement said. Thursday’s decision upheld an earlier ruling that was put on hold pending the opinion of medical experts.

A tribunal spokesman, Neth Pheaktra, said Ieng Thirith would be freed on Friday from the tribunal’s detention facility if prosecutors did not appeal.

Ieng Thirith was the Khmer Rouge’s minister for social affairs and the regime’s highest-ranking woman.

She also was the sister-in-law of late Khmer Rouge leader Pol Pot.

She is accused of involvement in the “planning, direction, co-ordination and ordering of widespread purges”, and was charged with crimes against humanity, genocide, homicide, torture and religious persecution.

Ieng Thirith has said that the charges against her are ”100 per cent false” and that she always worked for the benefit of the people.

The UN-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 1975-79 rule.

‘Mockery’ of justice

Three other senior leaders are currently on trial, including Ieng Thirith’s husband, 86-year-old Ieng Sary, the regime’s former foreign minister. Also on trial is 85-year-old Nuon Chea, the Khmer Rouge’s chief ideologue.

The tribunal’s statement stressed that Ieng Thirith’s release did not mean the charges against her were being withdrawn and that it was not a finding of guilt or innocence.

It plans to consult annually with experts to see whether future medical advances could render her fit for trial.

Survivors of the Khmer Rouge era were stunned, including 71-year-old Bou Meng, whose wife and two children were executed at the notorious S-21 prison in Phnom Penh.

“I am shocked,” Bou Meng said. “I had always hoped that the Khmer Rouge leaders would be brought to court for justice, but now they are freeing her.”

He called it “a mockery to the deaths of so many Cambodian people”, and asked, “Where is the justice for my dead wife and children?”