Certainly all of the readers here are familiar with the Khmer Rouge regime in Cambodia, under which cities were emptied and several hundred thousand "class enemies" liquidated. Estimates of the number of people killed cluster around 1.7 million, out of a population of 8 million. Count on the United Nations: within thirty years they have snapped into action and given the go-ahead for a tribunal to try those offenders that are still around.
Extensive documentation on the Cambodian genocide (or am I obligated to say "democide"? "politicide"?) is available in either eight or ten languages, depending on how you count, through Yale University's genocide studies program.