In 1949, Pol Pot went to study in Paris on a government scholarship. It was here that he got his introduction to Communism, joining the French Communist Party. After four years of exposure to Stalinist Communism he returned to Cambodia in 1953. Within a month he had joined the Communist resistance, becoming a member of the Indochina Communist Party (IHC) which was dominated by the Viet Minh.
Source: http://www.essortment.com/all/polpotbiograp_rxdy.htm Source:
And of course the same was true of Ho Chi Minh. From page 111 of Dr. Robert Turner's excellent 2004 paper, The Boston Manifesto:
Numerous biographies of Ho written and translated into English by Vietnamese Communists material that was readily available to any American who bothered to do a bit of research during the war openly discussed Hos role as a cofounder of the French Communist Party in 1920, his subsequent training in Moscow, and his three decades of employment outside Indochina as an agent of the Communist International (COMINTERN) promoting revolution around the world.