There is no evidence to suggest that Carlyle played any role in the repatriation of the Saudis, but public advocates argue that the Bush-Saudi ties create at least the appearance of a conflict of interest. “You would be less inclined to do anything forceful or dynamic if you are tied in with them financially,” says the Center for Public Integrity’s Charles Lewis. “That’s common sense.”

On September 18, 2001, a specially re-configured Boeing 727 flew at least five members of the bin Laden family back to Saudi Arabia from Logan airport.

On September 19, President Bush’s speechwriting team was working on a stirring address to be delivered the next day, officially declaring a global war on terror. “Our war on terror will not end until every terrorist group of global reach has been found, stopped, and defeated,” he would vow. At the Pentagon, planning was already under way to take this new war on terror all the way to Iraq.

That same day, the plane that had originated in Los Angeles and made stops at Orlando and Dulles airports arrived at Logan. It is unclear how many members of the bin Laden family or other Saudis had boarded prior to its arrival in Boston, but once it landed, at least 11 additional bin Laden relatives boarded the aircraft.

At the time, Logan was in chaos. The airport was reeling from criticism that its security failures had allowed the hijackings to take place. After all, the two hijacked planes that had crashed into the World Trade Center had departed from Logan. As a result, exceptional measures were now being taken. Several thousand cars were towed from the airport’s parking garages. “We didn’t know if they were booby-trapped or what,” says Tom Kinton, director of aviation at Logan.

The F.A.A. had allowed commercial flights to resume on September 13, as long as they complied with new security measures. Logan, however, because of various security issues, did not reopen until September 15, two days later. Even then, air traffic resumed slowly. So when a call came into Logan’s Emergency Operations Center in the early afternoon of September 19 saying that the charter aircraft was going to pick up members of the bin Laden family, Kinton was incredulous. “We were in the midst of the worst terrorist act in history,” he says, “and here we were seeing an evacuation of the bin Ladens!”

Bush, Baker, and Major flew to Saudi Arabia with Carlyle executives to meet with members of the royal family.

Like Kinton, Virginia Buckingham, then the head of the Massachusetts Port Authority, which oversees Logan, was stunned. “My staff was told that a private jet was arriving at Logan from Saudi Arabia to pick up 14 members of Osama bin Laden’s family living in the Boston area,” she later wrote in The Boston Globe. “‘Does the F.B.I. know?’ staffers wondered. ‘Does the State Department know? Why are they letting these people go? Have they questioned them?’ This was ridiculous.”

Only a few days earlier, some planes, such as the one carrying a heart to be transplanted to a deathly ill cardiac patient in Olympia, Washington, had been forced down in midflight. According to F.B.I. spokesman John Iannarelli, F.B.I. counterterrorism agents pursuing the investigation were stranded all over the country, unable to fly for several days. Yet now the same counterterrorism unit was effectively acting as a chaperone for the Saudis. Astonishingly, the repatriation was routed through Logan and Newark, two of the airports where, just a few days earlier, the hijackings had originated.

As the bin Ladens began to approach Boston, the top brass at Logan airport were agog at what was taking place. But federal law did not allow them much leeway to restrict individual flights. “I wanted to go to the highest authorities in Washington,” says Tom Kinton. “This was a call for them. But this was not just some mystery flight dropping into Logan. It had been to three major airports already, and we were the last stop. It was known. The federal authorities knew what it was doing. And we were told to let it come.”

Kinton and his co-workers were also told to let the other bin Ladens board and to allow the plane to leave and return to Saudi Arabia. As Virginia Buckingham put it, “Under the cover of darkness, they did.”

It was an inauspicious start to the just-declared war on terror. “What happened on September 11 was a horrific crime,” says John Martin, the former Justice Department official. “It was an act of war. And the answer is no, this is not any way to go about investigating it.”

Craig Unger is a Vanity Fair contributing editor.