No one really help or stop Cambodian genocide. Its liked when other victims of cruelty asked for help. No one really did something until the horrific events happened.
The Khmer Rouge were put in court. It was tough putting themselves on their place. Because of the little information we have on them. It took look a long time to put the perpetrators in court that most of them died. The people who were suspected were either killed in Vietnam, or murdered.