Vietnam invaded Cambodia in 1979, ending the short but deadly rule of the Khmer Rouge. Vietnamese troops discovered several killing fields as they poured into the country, climaxing in the discovery of s-21, where they found they found many prisoners freshly beaten to death, chained to iron bedframes. | Vietnam invaded Cambodia in 1979, ending the short but deadly rule of the Khmer Rouge. Vietnamese troops discovered several killing fields as they poured into the country, climaxing in the discovery of s-21, where they found they found many prisoners freshly beaten to death, chained to iron bedframes. |