Chheng Biography - Ly

His meticulous cross-referencing helped build the evidentiary foundation for the —the UN-backed tribunal that finally tried senior Khmer Rouge leaders like "Duch" (Kaing Guek Eav) and Nuon Chea.

"I learned to watch," he once told a researcher. "If you watched the guards, you could see the violence coming. If you watched the rice, you knew if you would eat. If you watched the sky, you knew when the bombing would stop. Watching became my profession."

"Justice is not just about prison cells," he says. "Justice is about a daughter knowing what happened to her father. Justice is about a village building a stupa of bones so the spirits can rest." ly chheng biography

Chheng has testified at the ECCC as a factual and expert witness. During one cross-examination, a defense lawyer suggested the documents could have been forged. Chheng responded calmly: "I was there. I held the paper. The paper does not lie. Only people lie." The ECCC concluded its work in 2022 with only three convictions. For many Cambodians, the tribunal was a failure—too slow, too expensive, too limited in scope. But Chheng refuses to see it that way.

That changed in 1995 when Yale University opened the . For the first time, there was a systematic effort to locate, preserve, and digitize the paper trail the Khmer Rouge had left behind. The regime was famously bureaucratic: they kept records of arrests, confessions (often tortured), and executions. If you watched the rice, you knew if you would eat

He turned back to his desk. On the screen was a scanned confession dated 1977. The prisoner had signed it with a shaky hand. Chheng adjusted the contrast, zoomed in on the signature, and added the name to a database.

When he identified the handwriting of his own primary school teacher on a Tuol Sleng execution order, he closed the file and went for a walk. He did not return to the document for three weeks. "Justice is about a daughter knowing what happened

When prosecutors needed to prove that the regime’s policies amounted to genocide against the Cham Muslim minority and the Vietnamese, they turned to Chheng’s spreadsheets. He created a relational database that matched prison logs with mass grave coordinates. He proved, beyond a reasonable doubt, that the killing was not chaotic but systematic.