From 1968 he led the Khmer Rouge, becoming Prime Minister soon after its seizure of power in 1975. During his regime the Khmer Rouge embarked on a brutal reconstruction programme in which more than 2 million Cambodians died. Overthrown by a Vietnamese invasion in 1979, Pol Pot led the Khmer Rouge in a guerrilla war against the new Vietnamese-backed government from his exile in Thailand. Following a split in the Khmer Rouge, he was captured by his former colleagues in 1997 and sentenced to life imprisonment: the cause of his death is unknown.