US special agents were told to back off the bin Laden family and the Saudi royals soon after George Bush became president, although that has all changed since September 11, it was reported today.
And the BBC2's Newsnight program also said the younger George Bush made his first million 20 years ago with an oil company partly funded by the chief US representative of Salem bin Laden, Osama's brother, who took over as head of the family after his father Mohammed's death in a plane crash in 1968.
The program said it had secret documents from the FBI investigation into the terror attacks on New York and Washington which showed that despite the myth that Osama is the black sheep of the family, at least two other American-based members of it are suspected of links with a possible terrorist organisation.
The program said it had obtained evidence that the FBI was on the trail of bin Laden family members living in the US after, and even before, September 11.
A document showed that special agents from the Washington field office were investigating Abdullah, a close relative of Osama, because of his relationship with the World Assembly of Muslim Youth (WAMY), a suspected terrorist organisation, it said.
The program said it had found where he used to live with another close relative, Omar, also an FBI suspect, in Falls Church, Virginia, a suburb of Washington. The house was conveniently close to WAMY, it said, and just a couple of blocks down the road was a place listed by four of the alleged hijackers as their address.
The US Treasury has not frozen WAMY's assets, and insists it is a charity, the program said, yet Pakistan had expelled WAMY "operatives" and India claimed WAMY was funding an organisation linked to bombings in Kashmir.
The FBI did look into WAMY, but for some reason agents were pulled off the trail, it said.
The program has uncovered a long history of shadowy connections between the State Department, the CIA and the Saudis, it said.
The former head of the American visa bureau in Jeddah from 1987 to 1989, Michael Springman, told the program: "In Saudi Arabia I was repeatedly ordered by high-level State Department officials to issue visas to unqualified applicants.
"People who had no ties either to Saudi Arabia or to their own country. I complained there. I complained here in Washington to Main State, to the inspector-general and to Diplomatic Security and I was ignored."
He added: "What I was doing was giving visas to terrorists - recruited by the CIA and Osama bin Laden to come back to the United States for training to be used in the war in Afghanistan against the then Soviets."
The US wanted to keep the pro-American Saudi royal family in control of the world's biggest oil spigot, even at the price of turning a blind eye to any terrorist connection - so long as America was safe, the program said.
The program said the younger George Bush made his first million 20 years ago with an oil company partly funded by the chief US representative of Salem bin Laden, Osama's brother, who took over as head of the family after his father Mohammed's death in a plane crash in 1968.
Young George also received fees as director of a subsidiary of Carlyle Corporation, a little-known private company which in just a few years of its founding has become one of America's biggest defence contractors, and his father, Bush Senior, is also a paid adviser, the program said.
And it became embarrassing when it was revealed that the bin Ladens held a stake in Carlyle, sold just after September 11, it added.
The program said it had been told by a highly-placed source in a US intelligence agency that there had always been "constraints" on investigating Saudis, but under President Bush it had become much worse.
After the elections, the intelligence agencies were told to "back off" from investigating the bin Laden family and the Saudi royals, and that angered field agents, the program added.
The policy was reversed after September 11, it reported.
The program was told by FBI headquarters that it could not comment on its findings.
A spokesman reportedly said: "There are lots of things that only the intelligence community knows and that no one else ought to know."