Montagnard

Earlier in the year Thailand also sent a Vietnamese Montagnard activist back to Vietnam.

The mountainous region in the Central Highlands was populated by Montagnard villagers, whom Army advisers — and before them, C.I.A. officers — tried to shape into a bulwark against the Vietcong, the Communist insurgency aligned with North Vietnam.

In 1992, Mr. Thayer followed the Vietnam War-era Ho Chi Minh Trail and encountered a lost group of the U.S.-allied Montagnard militia that did not know the conflict had been long over.

The case began in 2018, when a Facebook page critical of Sam Rainsy posted a video of a 2013 meeting he had in the United States with Kok Ksor, a leader of the ethnic Jarai hilltribe who headed the Montagnard Foundation, a U.S.-based organization representing the interests of hilltribe minorities who live in central Vietnam and northeastern Cambodia.

Around the corner was an old Montagnard man holding a long knife used to cut corn, ready to defend his family.