 Lon Nol saw Cambodia 's population of 400 @,@ 000 ethnic Vietnamese as possible hostages to prevent PAVN attacks and ordered their roundup and internment . Cambodian soldiers and civilians then unleashed a reign of terror , murdering thousands of Vietnamese civilians . On 15 April for example , 800 Vietnamese men had been rounded up at the village of Churi Changwar , tied together , executed , and their bodies dumped into the Mekong River . They then floated downstream into South Vietnam . Cambodia 's actions were denounced by both the North and South Vietnamese governments . 
 Lon Nol saw Cambodia <a href='null_genetive' title='1'><mark>'s</mark></a>population of 400 @,@ 000 ethnic Vietnamese as possible hostages to prevent PAVN attacks and ordered their roundup and internment . Cambodian soldiers and civilians then unleashed a reign of terror , murdering thousands of Vietnamese civilians . On 15 April for example , 800 Vietnamese men <a href='been_done' title='2'><mark>had</mark></a> been rounded up at the village of Churi Changwar , tied together , executed , and their bodies dumped into the Mekong River . They then floated downstream into South Vietnam . Cambodia <a href='null_genetive' title='3'><mark>'s</mark></a>actions <a href='uninflect' title='4'><mark>were</mark></a> denounced by both the North and South Vietnamese governments . 
Lon Nol saw Cambodia  population of 400 @,@ 000 ethnic Vietnamese as possible hostages to prevent PAVN attacks and ordered their roundup and internment . Cambodian soldiers and civilians then unleashed a reign of terror , murdering thousands of Vietnamese civilians . On 15 April for example , 800 Vietnamese men done been rounded up at the village of Churi Changwar , tied together , executed , and their bodies dumped into da Mekong River . They then floated downstream into South Vietnam . Cambodia  actions was denounced by both tdaNorth and South Vietnamese governments .