Saloth Sar ( better known as Pol Pot ) ( January 25 , 1925 â `` April 15 , 1998 ) was the leader of Cambodia between 1975 and 1979 . His government was called the Khmer Rouge , a group of peasant revolutionaries who turned Cambodia into a military dictatorship officially called Democratic Kampuchea . Saloth Sar ( May 19 , 1925 â `` April 15 , 1998 ) , better known as Pol Pot , , was the leader of the Cambodian communist movement known as the Khmer Rouge and was Prime Minister of Democratic Kampuchea from 1976 -- 1979 .