In early February of 1974, about 10 months before the Khmer Rouge takeover, Brigadier General Les Kosem and other leaders of Cambodia’s half million Cham Muslims gathered in Phnom Penh and made a public appeal for help.

Kosem read a resolution condemning Khmer Rouge atrocities against Sunni Muslim Cham, Cambodia’s largest ethnic minority. Muslim nations were also urged to assist in brokering peaceful negotiations.

The details of this long-ago event were embedded in thousands of previously unclassified but hard-to-access US diplomatic cables published on Monday by anti-secrecy website WikiLeaks. Dubbed the “Kissinger Cables” after then-US Secretary of State Henry Kissinger, they shed light on the lead-up to the fall of Phnom Penh, but also on once-prominent Cambodians who, like Kosem, may have slipped through the lines of most history books.

Kosem was close to the military apparatus supporting Lon Nol after the 1970 coup. He left Cambodia before the Khmer Rouge seized the capital and died abroad under mysterious circumstances. In the dwindling months of Lon Nol’s Khmer Republic, he kept busy by trying to build diplomatic ties with Muslim countries.

“At our meeting July 25, Prime Minister Long Boret gave me on confidential bases copy of General Les Kosem’s report on the Islamic Foreign Ministers Conference held [in] Kuala Lumpur from 21-25 June which he attended as head of a three-man delegation of Khmer Moslems,” read one cable from US Ambassador John Dean.

Kosem is remembered for his efforts to advocate for Muslims in danger and for attempting to spirit some of them out of the country.

“Despite his death, General Les Kosem is still well-known in the Cham Muslim community for his military position and [as a] representative for the Cham Muslim community at that time,” said Farina So, head of the Cham Oral History Project at the Documentation Center of Cambodia. “Cham Muslim leaders were trying to seek help from Malaysia, a Muslim country which is close to Cambodia, in the 1970s to help rescue the people from the communist control, but it did not work, because the situation was already worse, there was limited support and a lack of political will.”

After Phnom Penh was evacuated in April of 1975, the Khmer Rouge enlarged existing policies targeting religious groups. Seen as enemies, the Cham were hunted down, persecuted and killed by the thousands, their deaths serving as part of the basis for genocide charges in the Khmer Rouge tribunal’s Case 002.

According to So, the Khmer Rouge told some of the Cham that they were headed for Muslim countries in an exchange for oil, when they were really headed for work camps.

Kosem’s widow, Meidine Natchear, who runs a resort in Kampot, said her husband’s plan at the time was to bring all of the Cham to Malaysia. She says he succeeded in helping a couple thousand make the trip by boat with a stop in Thailand.

“He would never think about leaving Cambodia without his people,” she said.