Yasith left Cambodia in the early 1980s, amid the disarray following the Vietnamese invasion that deposed the Khmer Rouge régime from power.
In 1998, he established the Cambodian Freedom Fighters (CFF) an anti-communist organization and serves as its President.
The group's aim was to unseat the government of Prime Minister Hun Sen, a former Khmer Rouge commander who had defected to Vietnam in the 1970s and returned to Cambodia with the Vietnamese troops in 1979.
On November 24, 2000, dozens of rebels armed with rockets and grenades attacked government buildings in Phnom Penh.
[1] On June 22, 2001, the Cambodian Criminal Court found Yasith guilty and sentenced him to life in prison on charges of conspiring to commit terrorism, along with Richard Kiri Kim and Thong Samien.