Suffolk Square, the Jewish section of Malden, had no shortage of Holocaust survivors back in the 1950s, and Phillip Weiner knew many of them. They were the parents of his friends and the men at the bimah at his shul, Congregation Agudas Achim.

“You’d hear stories about how they had escaped and what life was like for them before; and you’d hear about their journeys to the United States,” he said.

Hearing stories of genocide at such a young age prepared Weiner for his later career in human rights law. After earning his law degree, he eventually became the chief prosecutor of organized crime in Suffolk County.

“I heard that the UN was looking for people in the ’90s. So, I applied and the District Attorney’s office let me go for a month,” he said.

Weiner’s experience in The Hague at the International Court of Justice, the main judicial arm of the United Nations, infused in him a calling to help people who have suffered enormous losses.

“The number and scale of the crimes in Bosnia was huge,” he said. “Two years later, the UN called and I returned full-time. I was engaged, but my fiancée told me to go for a year.”

One year turned into six. From 2001 to 2007, while living in The Hague, Weiner was a lead prosecutor on four trials involving atrocities in Croatia and Bosnia against civilians and prisoners of war. Crimes included torture, starvation, mass killing and acts of genocide committed in 1991 through 1995 during Yugoslavia’s breakdown.

While living in The Hague, Weiner also ran an intern program, which included Marblehead native Ben Weiner (no relation), then a senior at Boston College Law School.

In 2014, Weiner got a call from the UN asking him to serve on the Cambodian/UN court to oversee war crimes investigations relating to the Khmer Rouge regime. He was not inclined to go, but they kept calling.

“On the third or fourth time, they said, ‘we found you a synagogue,’” he remembered. “It’s called CHA-bad. So I laughed. I thought, if they’re looking for synagogues for me, they really want me.”

He went to Phnom Penh, Cambodia, and for five years served as the chief of staff at the Investigative Judge’s Office of the Khmer Rouge Tribunal to try the leaders of a regime that ruled from 1975 to 1979 and murdered 2.2 million people – 22 percent of the population.

Weiner recalled working on cases that were almost 40 years old and lacked necessary documentation. He also remembered going out in a UN-marked vehicle to view a field where there had been a mass grave beside a Buddhist temple.

“A neighbor across street waved to us. She wanted to grow vegetables on her front lawn and she hit a body – a woman in a bra, one and a half feet down. She was so close to the top. She had been buried quickly. This was an area where hundreds were killed,” said Weiner. “The whole country is a mass grave.”

Weiner interviewed witnesses and recorded testimonies of soldiers, survivors and victims of sexual assault. “There were mass killings of children, concentration camps, medical experimentation on human beings – similar to what the Nazis had done,” he said.

While in Cambodia, Weiner worked with Martin Karopkin, an international judge, from Brooklyn. They voluntarily helped improve the local legal system by training judges, attorneys, and the police for four years. Last year, the Kingdom of Cambodia awarded Weiner a knighthood in honor of his work.

Seeking a sense of community so far from home, Weiner and Karopkin became the leaders of the Jewish community at the court in Cambodia, and brought the Jewish attorneys and interns to a Chabad synagogue. Every Friday night, Weiner and Karopkin, two legal scholars investigating the most heinous modern war crimes, went to synagogue together to find peace and to regenerate their souls.

Phillip Weiner will speak on ‘The Khmer Rouge and the Killing Fields of Cambodia,’ on Sunday, Feb. 23 at Temple Sinai at 7:15 p.m.