The Rafael Martínez Pupo Papers Relating to Comandos Mambises Collection contains Martínez Pupo's correspondence with Cuban exiles, news agents, and government officials as well as expense reports, receipts and newspaper clippings from U.S. and Latin American newspapers of the commando's attacks on Cuban soil.
During the 26th of July Movement, Martínez Pupo sent convoys of provisions and supplies to the rebels, only later to see Fidel Castro nationalize his belongings and his business empire in 1959. In 1960, he and his family went into exile. While his daughter and her family remained in Miami, he and his wife went to Guatemala. In 1963, the CIA recruited Martínez Pupo to lead a campaign of guerrilla warfare and sabotage by a commando group constituted by Cuban exiles. He called this group Comandos Mambises in honor of the Cuban insurgents who fought against Spain. The unit's mission was to sabotage strategic targets in Cuba in order to inflict economic and psychological damage to Castro's regime.