Son Sen
In 1997, Pol Pot ordered the execution of his right-hand man Son Sen for attempting peace negotiations with the Cambodian government. In 1998, Pol Pot himself died, and other key KR leaders Khieu Samphan and Ieng Sary surrendered to the government of Hun Sen in exchange for immunity from prosecution, leaving Ta Mok as the sole commander of the Khmer Rouge forces; he was detained in 1999 for "crimes against humanity." The organization essentially ceased to exist.