REHOBOTH -- When he was 10, Kosal Phat stumbled on a pile of human skulls near his home in Cambodia while tending his family's cows.

The skulls, part of a massacre committed during the 1970s by the Khmer Rouge, awakened horror in Phat, and set the young man on a path to seek justice for his murdered countrymen.

`` It was in a suburb not far from my village,'' said Phat, who spoke to seventh-grade students Friday at the Beckwith Middle School. `` When I found them, I went home and asked my parents if they knew what had happened there. They said there had been a massacre there by the Khmer Rouge.''

Phat is currently a member of a documentation project gathering evidence of crimes by the former Cambodian government. A small boy during the Pol Pot regime blamed for the deaths of 1.7 million Cambodians, Phat remembers little of the cruelty that took the lives of 10 family members.

`` My aunt was forced to marry a cadre member,'' said Phat. `` One night, she came and hugged me and the next day she was gone. My parents learned that she had hanged herself.'' Phat was accompanied Friday by Susan Cook, director of the Yale University Cambodian Genocide Program. Cook, a former Rehoboth resident, said students can help stop government-sponsored killing in the future by protesting rogue regimes and letting their elected representatives know they're concerned.

`` Genocide is still happening, and it happens all around the world,'' said Cook. Even 55 years after the Holocaust, she said, systematic killing of religious groups and minorities continues to spring up in places like Rwanda, Yugoslavia and East Timor.

Phat said his encounter with the skulls spurred him to seek answers about what had happened to his countrymen. In college, he volunteered with a group that sought to expose Khmer Rouge atrocities.

In the last several years, he said, investigators have discovered more than 500 `` genocide sites'' in Cambodia containing mass graves and other evidence of barbarity.

In a short film shown to students Friday, Phat and co-workers were shown interviewing survivors of a prison camp in northwestern Cambodia. Former prisoners told of being imprisoned for hiding food and of being beaten and starved by their captors.

Probing evidence of wrongdoing in Cambodia can be dangerous. Even a generation after Vietnamese forces evicted the Khmer Rouge from power, some former government officials still live in close proximity to the people they brutalized.

In the movie, government soldiers accompanied Phat's team to protect them and to check for mines that are sometimes left behind to intimidate the curious.

Phat, whose family still lives in Cambodia, said the present Cambodian government is preparing to hold a UN-backed tribunal to punish those responsible for the killing. Despite the passage of nearly a quarter century since the fall of Pol Pot, Phat is confident that justice will prevail.

`` I believe we have quite a lot of evidence,'' he said.

RICK FOSTER can be reached at 508-236-0372 or via e-mail at rfoster@thesunchronicle.com.