Prince Turki al-Faisal (Prince Turki bin Faisal ibn Abdul Aziz Al Saud) (1945-) is a senior member of the House of Saud, the ruling family of Saudi Arabia. He was the last son of the late King Faisal. He has been called both one of the most Westernized and one of the most anti-American princes, and has had a major role in the foreign policy of Saudi Arabia.
After primary schooling in the Kingdom, he attended U.S. secondary schools and took an undergraduate degree (1968) at Georgetown University, where Bill Clinton was a classmate, and did some graduate work in Britain.
From 1977 to 2001, he served as the Director General of the General Intelligence Department (GID) (Istakhbarat). This was Saudi Arabia's interface to Pakistan's Inter-Service Intelligence for activities associated with the Afghanistan War (1978-1992). It sponsored Abdul Rasul Sayyaf as the warlord best representing Saudi interests.
Turki would enforce the bounds of the relationship between the Wahabbi clergy and the House of Saud. He had a highly visible public confrontation with an imam who had called five women of the royal family, who ran a charity, whores. While this incident ended with an apology, Turki's service, which was not authorized to operate domestically, began to monitor the muttawa religious police, who represented a threat. By doing so, he challenged Prince Naif, the head of the Interior Ministry.
In 1990, he was involved in discussions in which the Kingdom rejected Osama bin Laden's offer to defend the Kingdom after the Iraqi invasion of Kuwait. The Saudi choice to accept American assistance, according to Turki, infuriated bin Laden and cause a fundamental change of relationship.
Sudan, in 1996, has been reported to have offered to extradite bin Laden to Saudi Arabia. There are various acounts of the relationship between the Saudis and bin Laden; other reports from Jamal al-Fadl said they had planned to assassinate him. President Bill Clinton called the Prince and encouraged the extradition, assuming the Saudis would execute bin Laden. The idea was rejected, but bin Laden left Sudan.
Events surrounding 9/11
An announcement, on 31 August 2001, said "Custodian of the Two Holy Mosques King Fahd bin Abdulaziz yesterday relieved Prince Turki Al-Faisal bin Abdulaziz, upon his own request, from his post as Chief of General Intelligence." Whether a resignation or firiing, this surprised outside observer; Fahd had recently reconfirmed him and he was a close ally of Crown Prince Abdallah.
"Other speculation focused on the fact that his departure came a few days before September 11th. One conjecture suggested that Turki had found out about the planned attacks and was trying to dissuade bin Laden. His failure to do so, or his failure to report his prior knowledge, could have precipitated his dismissal as intelligence chief. "
He was named Ambassador to Great Britain in 2002. In an independent but pro-government newspaper, he said
Saudi Arabia has worked with the United States for the past 70 years. Both countries have benefited from this enduring partnership. Remember that we face the same threat: Bin Ladin targeted Saudi Arabia before he targeted America. Al-Qa'ida has thousands of followers from more than 60 countries, including those of many U.S. allies. That he chose 15 Saudis for his murderous gang, many of whom, he boasted, did not even know the ultimate goal of their mission, can only be explained as an attempt to disrupt the close relationship between our two countries.... There are those in America who condemn all Saudi Arabians as uncivilized, close-minded and barbaric. But such blanket accusations are not worthy of the American people.... Let us deny extremists the victory of undermining our partnership. Instead, let us remain strong, and, whatever shortcomings we see in each other, let us confront them and overcome them together in a spirit of mutual respect and openness.
He, along with Prince Sultan bin Abdul Aziz and Prince Mohammed bin Faisal, were sued in U.S. court in August 2002, claiming they had funded Osama bin Laden, and at least indirectly financed the 9-11 attack. They were ruled immune and the suit dismissed in 2005, although appeals continue. 
Ambassador to the U.S.
Prince Turki became Ambassador to the United States in 2005, but left after a short 15 months. A wide range of explanations have been offered. One is that he was simply to take on more responsibilities in the Kingdom, as one of the inner circle with foreign policy experience. Another is that he was criticized for a Saudi proposal regarding financing Sunnis in Iraq if the U.S. left; the article also suggested tensions among the King, Prince Turki, and Prince Bandar. 
- Lawrence Wright (2006), The Looming Tower: Al-Qaeda and the Road to 9/11, Alfred A. Knopf, ISBN 037541486X, p. 100
- Wright, The Looming Tower, pp. 148-149
- "Prince Turki bin Faisal ibn Abdul Aziz Al Saud", Globalsecurity
- Arab News, 18 September 2002, quoted by Globalsecurity
- CBS News, 31 May 2009
- Helene Cooper (December 13, 2006), "Saudis Say They Might Back Sunnis if U.S. Leaves Iraq", New York Times