The National Review carried this story, "The bin Ladens' Great Escape: How the U.S. Helped Osama's Family Leave the Country After 9-11", which was published on September 11, 2002. An excerpt:

While FBI agents looked into bin Laden family members in the Boston area immediately after September 11, it appears that the agents' first chance to interview them — or other family members who lived elsewhere in the country — came on the day they left the U.S. Each family member was given the all-clear on the basis of a single, day-of-departure interview — conducted, in Bill Carter's words, "at the airport, as they were about to leave."

Asked by National Review whether the FBI had conducted a full and thorough investigation of all the family members before allowing them to go, Carter repeated his earlier statement: "The FBI had an opportunity to interview the individuals on that plane, and we were satisfied with the information they provided." Asked again, he said the same thing. "Unless you have evidence to stop them from leaving the country, they have every right to do that," Carter explained. "The bin Laden family is very large, and for the most part are involved in legitimate enterprises. The fact of the matter is that because of September 11, some of these individuals felt it would be better to leave the country. They have every right to do that."

[Bill Carter is earlier identified as an FBI spokesman for the case.]

There is no direct mention of any specific individuals, or a specific number of individuals, in the family with links to WAMY, though two members of the family are mentioned by name in connection with investigations of terrorist financial support systems.

Apparently, the flight itself, and the rubberstamp exit interviews, are verified.

I myself come up short when I look at claims that Bush knew ahead of time about the 911 attacks. But when I look at this, I see a clear obstruction of a multiple-felony investigation. What do you do when the branch of government whose Constitutional duty it is to enforce the law obstructs a criminal investigation?

It disturbs me that, at a time when we are told that we must abandon our right to be left alone as American citizens in the name of "public safety"* and patriotism, at a time when countless foreign nationals have been rounded up and held incommunicado, sometimes for months, so they could be thoroughly interviewed, a whole group of people who may have had Osama's cell phone number on speed dial were let go within a week of mass murder because the Saudis have a cozy relationship with the White House.

Regards--
Mary Anne

*what I'm thinking of when I use this phrase
"'La terreur n'est autre chose que la justice prompte, sévère, inflexible.' ('Terror is nothing other than prompt, severe, inflexible justice.')" --Maximilien Robespierre