The Libyan Foreign Minister Moussa Koussa who defected to Britain this week had been working with the CIA, according to Vince Cannistraro, a former CIA official.
Mr Cannistraro told NPR that Koussa had been in contact with American authorities over counterterrorism issues.
The former senior official developed a close working relationship with Washington when he was the head of Libya’s intelligence service, a few years ago.
The CIA official was stationed in Italy in the late 1980s when Koussa was head of Libya’s intelligence service.
The US believed Libya to be a serious terrorist threat in the 1980s and 1990s, after the bombing of Tripoli by US jets.
At the time, the international community had imposed severe economic sanctions on the country.
But Libya once again became useful to Americans following the September 11, 2001 terrorist attacks, when Mr Koussa convinced Moammer Gaddafi to give up nuclear weapons and make the US an ally.
Libya then turned various al-Qaeda operatives in the country to American authorities.
Koussa had been in the US in the 1970’s when he graduated from Michigan State University with a degree in sociology.
Koussa resigned as Libya’s foreign minister and defected to Britain on Wednesday, even as troops loyal to Gaddafi clashed with rebel forces.