Cambodia’s United Nations-backed court set up to try Khmer Rouge leaders is finishing its work this week, ending a 16-year process that has helped national reconciliation but only benefited the survivors of the genocidal regime brought limited comfort.

The Extraordinary Chambers of the Cambodian Courts (ECCC) will on Thursday rule on the appeal of 91-year-old former head of state Khieu Samphan against his 2018 conviction for genocide and crimes against humanity.

It will be the final verdict from the tribunal, which has cost more than $330 million and has been dogged by complaints about the slowness of its work and allegations of interference from the Cambodian ruling party.

For Chum Mey, one of only a few survivors of the infamous S-21 torture prison, nothing will erase the trauma of the Khmer Rouge massacre of his wife and four children.

“It’s only when I die that I can forget everything,” Chum Mey told AFP at S-21, once a school and now a museum chronicling Khmer Rouge atrocities.

Under leader Pol Pot, two million Cambodians died of starvation, torture, forced labor and mass executions – almost a quarter of the kingdom’s population was wiped out by the ultra-communist regime as it attempted to create an agricultural utopia.

Khieu Samphan is one of only three senior leaders convicted by the Special Court, along with “Brother Number Two” Nuon Chea – believed to be the regime’s chief ideologue – and S-21 prison warden Kaing Guek Eav, better known as Duch.

Two previous appeals were unsuccessful – in fact, the court increased Duch’s sentence on appeal.

The court had a difficult birth. In 1997, the Cambodian government asked for UN help in judging Khmer Rouge leaders.

But it rejected the idea of ??another International Criminal Court along the lines of those created for the former Yugoslavia and Rwanda, insisting on a sovereign court headed by Cambodian and international judges.

Finally, an agreement was reached in 2003, but the first hearing – in the Duch case – did not take place until 2009.

In all, five senior Khmer Rouge cadres, all older, stood trial, but two died during the trial and two others – Duch and Nuon Chea – died after sentencing.

Regime leader Pol Pot died in 1998 before the court was set up, while three others accused of genocide and crimes against humanity are not being tried due to disagreements between Cambodian and international judges.

S-21 survivor Chum Mey, who testified in 2009, said the court was only “about 70 percent right,” but his work was valuable nonetheless.

“The most important thing is that the court prosecuting the Khmer Rouge leaders let people across the country know about Pol Pot’s killings so they don’t let it happen again,” the 91-year-old said.

Another source of controversy was the court’s limited jurisdiction, which allowed it to prosecute only senior Khmer Rouge leaders.

Exiled opposition leader Sam Rainsy says the decision effectively shielded Prime Minister Hun Sen – a former Khmer Rouge commander who has ruled the country since 1985.

The strongman PM has repeatedly warned against escalating the scope of the trials as it could endanger national stability.

“The court has a decidedly mixed heritage, a mix of solid achievements and disappointing failures,” said Craig Etcheson, author of several books on Cambodia, including one on the special court.

However, the tribunal helped “advance the process of national reconciliation,” Etcheson said.

“Parents feel more free to talk to their children about what happened to them… Schools added new materials about the Pol Pot period to their curricula, neighbors started talking to neighbors about their experiences,” he said.

Almost a quarter of a million people attended the hearings, at which more than 300 witnesses, civil parties and experts gave evidence.

Etcheson argues that the court was “a relative steal” compared to other international tribunals and that the donors were “far too stingy,” which caused delays in the process.

Youk Chhang, director of the Cambodia Documentation Center, which conducts research on the Khmer Rouge regime, says it is a mistake to focus on the court’s financial affairs.

“It confirms that we can live after genocide – that we can move on, that we can rebuild, we can reset what has been lost,” he said.

Back at S-21, the somber black-and-white photos of over 18,000 murdered inmates are displayed in the exhibition halls.

Survivor Bou Meng, 85, who still bears the physical and mental scars of his time here, calls for handcuffs and chains to surround the graves of dead Khmer Rouge leaders.

“I will remember everything for the rest of my life,” he said. “They beat me, they tortured me, I can never forget those things, it’s still fresh and alive.”