Conversation so far:
When was the separatist movement?
Headed by a Khmer Krom Buddhist monk, Samouk Sen, the group was nicknamed the "White Scarves" .
what was special about them?
allied itself with FULRO against South Vietnam.
was this helpful?
The "White Scarves" arrived in Kiri Vong District in 1976, making overture to the Khmer Rouge.
Are there any other interesting aspects about this article?
Subsequent orders from the Khmer Rouge leadership however had Samouk Sen arrested, taken to Phnom Penh, tortured, and killed.
were any others killed?
His force of 67 Khmer Krom fighters were all massacred.

Question: why were they killed?
Self-contained rewrite: why were Samouk Sen 's force of 67  Khmer Krom fighters killed?