Son Sen was a Cambodian Communist politician and soldier. A member of the Central Committee of the Communist Party of Kampuchea/Party of Democratic Kampuchea, the Khmer Rouge, from 1974 to 1992, Sen oversaw the Party's security apparatus, including the Santebal secret police and the notorious security prison S-21 at Tuol Sleng.
Sen was married to Yun Yat, who became the Party's minister of education and information. Along with the rest of his family, he was killed on the orders of Pol Pot during a 1997 factional split in the Khmer Rouge.