Manolo de Souza was a U.S. national.
Jack hired Manolo to place thirty pounds of semtex explosives at a safe house in Madagascar in order to make Sydney believe that Irina was going to betray them. Manolo merely asked why he needed to use so much explosives before he headed to Madagascar to plant the semtex (Dead Drop).
Shortly after planting the explosives (which were accidentally set off thanks to Sark's men), Manolo was caught by Madagascar customs transporting explosives out the country. He was transferred over to the CIA headquarters in Los Angeles, where he was scheduled to be taken to New York. Vaughn quickly headed over to see Manolo, where he first bribed Manolo into talking by offering him a soda. After getting no response, Vaughn threatened Manolo by saying he'd be put in prison for the rest of his life. Just as Vaughn was about to leave, Manolo stopped him and told him that he was working for the CIA, specifically for Jack Bristow (The Indicator).