Ta Mok, the notorious former Khmer Rouge military commander and central committee member nicknamed "The Butcher," died recently. His death, like that of Pol Pot in 1998, deprives Cambodians of yet another chance to see a key architect of the Cambodian genocide held accountable for the campaign of mass murder unleashed from 1975 to 1979.

Ta Mok's passing was filled with ironies. Most immediate was the incongruous sight of his being given an elaborate Buddhist funeral, replete with 72 chanting monks, and being laid to rest in a concrete monument on the grounds of a temple. This was a strange end for a man who had helped implement the Khmer Rouge ban on Buddhism and a policy of dumping victims unceremoniously in mass graves.

The timing was also ironic. Just a few weeks earlier, the legal personnel for the Extraordinary Chambers in the Courts of Cambodia were sworn in, initiating a U.N.-sponsored trial of former Khmer Rouge leaders that has been 27 years in the making. Ta Mok, arrested in 1999 and awaiting trial ever since, was expected to be one of the first and most important defendants to be tried.

After nearly three decades of delay, Ta Mok's death underscores the urgency of pressing forward with the tribunal as quickly as possible. Other likely candidates for prosecution, including "Brother Number Two" Nuon Chea, 79, former state presidium chief Khieu Samphan, 77, and Ieng Sary, 76, the former deputy prime minister of foreign affairs, could, like Ta Mok and Pol Pot, die as free men, unjudged.

Ta Mok's dirty work litters the landscape of his country. In January I traveled to parts of southwest Cambodia, the area that he governed with an iron grip during the genocide — as evinced by dozens of former prison camps and as many as 6,000 mass graves. In many places the bones of the dead are piled high in shrines, serving as evidence of mass murder and as memorials to the past. I interviewed former prison guards who told me with downcast eyes that they didn't do anything and, besides, they were only following orders. And I spoke with former prisoners who continue to live in fear of such men and who are still tormented by the past.

Three things about the tribunal emerged clearly during my trip.

First, there needs to be more focus on outreach. While many people know at least a little about the Extraordinary Chambers, it was disconcerting to meet others who didn't even know that a trial was going to take place, what an international tribunal was or who might be tried. If the Extraordinary Chambers are to be successful, they need to mean something to these people.

Sadly, outreach is often one of the "soft money" items donors look to trim from a budget. The international community must make sure this does not happen in Cambodia.

Second, the United States needs to get involved. After I gave a talk at the Club of Cambodian Journalists, several Cambodian journalists asked me why the United States was not supporting the tribunal. I didn't have a good answer, explaining that the lack of U.S. involvement was due to political maneuvering and concerns about the independence of the Cambodian legal personnel who are working alongside international jurists and lawyers in this "mixed" tribunal. While this latter concern necessitates vigilance, U.S. involvement would increase the tribunal's chances of success. Besides, we have a responsibility to help out, given our country's dismal legacy in Cambodia. A first step would be for the United States to cover part or all of the $9.6 million shortfall in funding for the Extraordinary Chambers.

Third, there is an urgent need to enhance Cambodia's mental health programs. One of the risks of a tribunal is reopening or exacerbating psychological wounds, a possibility that is all the more alarming in Cambodia because the country has a minimal mental health infrastructure outside of the urban areas — in part due to the loss of almost all of Cambodia's psychiatrists during the Khmer Rouge period. Recent research and my own conversations with people in the countryside suggest that many Cambodians continue to suffer from bodily ailments, flashbacks and nightmares. The international community must act immediately to avert a potential mental health crisis in Cambodia as the tribunal proceeds.

To date, not a single high-ranking Khmer Rouge leader has been held accountable or has taken responsibility for the death of as many as 2 million Cambodians — roughly a quarter of the population. Like Ta Mok, these leaders show little remorse and blame Pol Pot for everything.

Many Cambodians were understandably outraged that he cheated justice. They want the former Khmer Rouge leaders to be tried. The international community must act to ensure this happens in a swift and meaningful manner — before it's too late.

Alex Hinton is associate professor of anthropology at Rutgers University at Newark and the author of "Why Did They Kill? Cambodia in the Shadow of Genocide." He wrote this commentary for the Washington Post.