Suffering from high blood pressure and heart problems, Ieng, 87, entered hospital on March 4 and died before any verdict was reached in his case, dashing hopes among survivors and prosecutors that he would ever be punished for his alleged crimes against humanity and genocide.

Ieng, who was arrested in 2007, had been on trial since 2011 before a joint Cambodian-international tribunal along with two other former Khmer Rouge leaders, both in their 80s. There are fears that they, too, could die before justice is served.

"We are disappointed that we could not complete the proceedings against Ieng Sary," said tribunal spokesman Lars Olsen, who said the case against Nuon Chea, the Khmer Rouge's chief ideologist, and Khieu Samphan, an ex-head of state, will continue and will not be affected.

Ieng founded the Khmer Rouge with Pol Pot, his brother-in-law. The regime, which ruled Cambodia from 1975 to 1979, claimed it was building a pure socialist society by evicting people from cities to work in labor camps in the countryside. The Khmer Rouge's policies led to the deaths of an estimated 1.7 million people from starvation, disease, overwork and execution.

Ieng Sary's wife, Khmer Rouge Social Affairs Minister Ieng Thirith, was ruled unfit to stand trial last year because she suffered from a degenerative mental illness.

‘Facilitated arrests and executions'

The Khmer Rogue toppled Cambodia's US-backed regime in a civil war. Ieng helped persuade hundreds of Cambodian intellectuals to return home from overseas, often to their deaths. The Khmer Rouge arrested the returning intellectuals and put them in "re-education camps," eventually executing them, said Youk Chhang, the director of the Documentation Center of Cambodia, an independent group gathering evidence of the regime's crimes for the tribunal.

As the Khmer Rouge's foreign minister, Ieng became a much more recognizable figure internationally than his secretive colleagues. In 1996, he defected from the movement, which secured him a limited amnesty, temporary credibility as a peacemaker and years of comfortable living in Cambodia. But that vanished as the UN-backed tribunal built its case against him.

Ieng "repeatedly and publicly encouraged, and also facilitated, arrests and executions within his Foreign Ministry and throughout Cambodia," Stephen Heder, a Cambodia scholar who later worked with the tribunal, wrote in "Seven Candidates for Prosecution: Accountability for the Crimes of the Khmer Rouge," the 2001 book he co-authored with Brian Tittemore.  

Mass executions

Known also as "Comrade Van," Ieng received several internal Khmer Rouge documents that detailed torture and mass execution of suspected internal enemies, according to the Documentation Center of Cambodia.

"We are continuing to wipe out remaining (internal enemies) gradually, no matter if they are opposed to our revolution overtly or covertly," read a cable sent to Ieng Sary in 1978. The Documentation Center reprinted the cable in 2000, apparently proving that Ieng had full knowledge of bloody purges.

"It's clear that he was one of the leaders that was a recipient of information all the way down to the village level," Youk Chhang said.

mkg/jm (AFP, dpa, AP)