The town, close to the Thai border, was home to four of the five former Khmer Rouge leaders currently awaiting trial.
But finding witnesses to take part in the United Nations-backed trials has not been easy, with many former Khmer Rouge members worried they may also be punished.
People's help needed
The tribunal has been delayed for many years and is jointly overseen by Cambodian and international judges.
But officials say without the help of the people, it will struggle to fulfil its mandate.
"We were trying to explain to these people that the court can proceed fairly as long as it has the support of the Cambodian people," Marcel Lemonde, a French co-investigating judge told one of the meetings in Pailin.
"If the Cambodian people do not understand that this trial is in their interests, this court will not be able to proceed fairly."
Up to two million people died during the Khmer Rouge's four years in power between 1975 and 1979.
Pol Pot, the group's former "Brother Number One" died in 1998, but five senior figures of his regime are being held awaiting trial, including his deputy, Nuon Chea, or "Brother Number Two".
Few Cambodian families were untouched by the slaughter, but in Pailin - home to many former Khmer Rouge foot soldiers – the tribunal has been met with scepticism.
Late last year the tribunal held its first hearing in an appeal by the former commander of the Khmer Rouge's S-21 detention and interrogation centre against his continued detention.
Kaing Guek Eav, also known as Duch, claimed that his human rights had been violated by being held for more than eight years in jail without trial.
|An estimated two million Cambodians died |
under the Khmer Rouge [AFP]
But the tribunal rejected his appeal, saying he might try to flee the country or threaten potential witnesses if he were released on bail.
Aside from Duch and Nuon Chea the other former Khmer Rouge officials awaiting trial include the regime's former foreign minister, Ieng Sary, his wife and former social affairs minister, Ieng Thirith, and the former president of the Khmer Rouge, Khieu Samphan.
The first formal trials are expected to begin later this year.