With Ieng Sary's death on Thursday, Cambodians were robbed of a verdict against one of the handful of elderly ex-Khmer Rouge leaders brought before a UN-backed war crimes court.
Following are brief profiles of the accused still on trial and those who have avoided justice since their arrests in 2007:
-- NUON CHEA: "Brother Number Two" to ruthless Khmer Rouge leader Pol Pot, the ailing 86-year-old -- who defected to the government in 1998 -- is believed by researchers to have been a key architect of the regime's death machine.
Since surrendering to the government under a deal that doomed the Khmer Rouge, Nuon Chea has acknowledged the deaths that took place under the regime but denies that he was in a position to stop the disaster.
-- KHIEU SAMPHAN: A French-educated radical, Khieu Samphan served as head of state for Pol Pot's regime, and was one of the regime's few diplomats who had contact with the outside world.
The 81-year-old has never admitted to a role in the regime's brutal excesses. Instead, he has styled himself as an intellectual and nationalist who claims he knew little, until long afterwards, of the devastation that was wrought during the Khmer Rouge's nearly four years in power.
He defected to the government side with Nuon Chea in 1998, the year of Pol Pot's death.
THE COUPLE WHO ESCAPED JUSTICE
-- IENG SARY: Known as "Brother Number Three", he co-founded the Khmer Rouge and served as foreign minister under Pol Pot, who was also his brother-in-law.
He died in hospital on Thursday aged 87 without a verdict on his role in the regime ever being reached. He was a young radical at university in France before he emerged as one of the few public faces of the Khmer Rouge during its brutal rule.
Ieng Sary was found guilty of genocide in a 1979 Vietnamese-backed trial, widely regarded as a sham. He was granted a royal amnesty in 1996 after he defected to the Cambodian government.
-- IENG THIRITH: The most powerful woman in the Khmer Rouge, Ieng Thirith, 81, was Ieng Sary's wife and Pol Pot's sister-in-law. She was declared unfit to stand trial in September last year after diagnosis with a degenerative disorder -- likely to be Alzheimer's disease.
Sometimes described as the "First Lady" of the Khmer Rouge, she acted as social affairs minister and is held responsible by some researchers for the regime's drastic re-ordering of traditional Cambodian life.
An intellectual who studied English literature in Paris, Ieng Thirith plunged into radical politics after becoming involved with Ieng Sary in France and remained a staunch defender of the Khmer Rouge long after the regime's demise in the 1990s.
In 2009 she said "everything was done by Nuon Chea" and told her accusers they would be "cursed to the seventh circle of hell".
THE ONLY ONE CONVICTED:
-- KAING GUEK EAV: The Khmer Rouge torture chief -- better known as Comrade Duch -- once taught maths to schoolchildren, but went on to head the regime's most notorious jail.
The now 71-year-old oversaw the extermination of around 15,000 men, women and children at the Tuol Sleng prison in Cambodia's capital during the communist regime's brutal 1975-1979 rule.
He was initially sentenced to 30 years in prison in 2011 for war crimes and crimes against humanity but the term was increased to life on appeal.
Duch had asked to be acquitted on the grounds that he was not a senior member of the Khmer Rouge hierarchy.
"I respectfully and strictly followed the orders," Duch said in his final public statement to the court during his appeal.
THE OTHERS WHO ESCAPED JUSTICE:
-- "Brother Number One" Pol Pot died in 1998 at the age of 73 while under house arrest by Khmer Rouge rebels who had turned against him.
-- Ta Mok, a feared military commander nicknamed "The Butcher" for the massacres and purges he ordered, was arrested in 1999. He was awaiting trial by the war crimes court but he died in 2006 at the age of 80.
Because of the tribunal's limited scope, thousands of lower-level Khmer Rouge members and fighters who carried out the regime's brutal acts will also never face the court.