Observers following the troubled Khmer Rouge war crimes tribunal say an escalating dispute with the Cambodian government makes it increasingly unlikely that new charges will ever be brought against remaining suspects.
The United Nations-backed court has already sentenced one former Khmer Rouge official to life in prison, and is hearing a second case against the group's three top surviving leaders.
But Clair Duffy, who follows the trial for the Open Society Justice Initiative, tells VOA the highly controversial cases 003 and 004 will probably not move forward without the support the Cambodian government, which is on record as opposing any new investigations.
"I can't see those cases moving forward, as in any suspects ever being arrested or prosecuted, without the [Cambodian] government's full cooperation. And in the time that I've been monitoring these proceedings, the government has not budged a single millimeter," said Duffy.
The Cambodian government, which includes many former Khmer Rouge members, has voiced strong opposition to pursuing more cases, saying any further prosecutions could divide Cambodian society and spark a civil war.
Last week, the United Nations promised to replace two international investigating judges who resigned in recent months complaining of improper interference in their work. But the world body warned it still has "serious concerns" about the judicial process, saying it is "essential" that the Cambodian government extend "full cooperation" to the new judges.
Duffy says the U.N. should go one step further. Her organization is calling for a full investigation into the government's behavior toward the court, saying the legacy of the tribunal itself is at risk.
"We started calling for a full inquiry by an independent panel of experts into political interference in the court. Really, it's not enough to appoint another judge. We've been saying all along this is commission of inquiry material here," said Duffy.
In March, Swiss Judge Laurent Kasper-Ansermet resigned, saying he could not continue his work because of repeated challenges to his authority by his Cambodian counterpart on the tribunal, You Bunleng.
The Swiss jurist joined the tribunal earlier this year to replace German investigating judge Siegfried Blunt, who quit in October after also complaining of political interference.
The hybrid Cambodian-international tribunal is investigating war crimes and crimes against humanity in the deaths of some 1.7 million Cambodians who died during the 1975-1979 rule of the Khmer Rouge.
The U.N. says the court also faces a "serious funding challenge" from international donors, who seem to be increasingly losing faith in the tribunal, which has spent more than $150 million since its formation in 2005.