After 1975
Subsequent to the 1975 Khmer Rouge victory and the proclamation of Democratic Kampuchea, the few remaining "Free Khmer" operating in the north-west, in the area of the Dangrek Mountains, found themselves mostly in refugee camps along the Thai-Cambodian border, such as Nong Chan and Nong Samet. Son Sann was to use some of these former Khmer Serei supporters as the basis of the Khmer People's National Liberation Front movement, formed in 1979.
Thanh himself was to die in Vietnamese custody in 1977.
Read more about this topic: Khmer Serei