Sin Sisamouth was the Cambodian equivalent of Elvis, massively popular during the 1960s- early 70s. When the Khmer Rouge took power on April 27th 1976 and forced the evacuation of Phnom Penh, he was seen leaving the city with others. This was the last anyone had ever seen or heard from him. His body has never been found, and any record of him from April 27th 1976 onwards doesn't exist.