In case the import is not clear, let us state emphatically: this is a huge development.
In court filings seeking to stave off a media Freedom of Information request, the FBI has stated that releasing documents relating to this issue will harm "national security." As proof of the sensitivity of the matter, the FBI gave the judge a document dated April 4, 2002, in which the FBI states that its own inquiries "revealed many connections" between a well-connected Saudi family with a house in South Florida and "individuals associated with the terrorist attacks on 9/11/2001."
The Sarasota Affair
The Freedom of Information request that prompted these reluctant admissions was filed by the Broward Bulldog, a South Florida nonprofit investigative site which first covered the Saudi connection in 2011.
The Bulldog's reporting explained how a family living in an exclusive gated community outside Sarasota, on Florida's West Coast, had apparently vanished suddenly some 10 days before the 9/11 attacks. Investigators, including a swarm of FBI agents, found that the family's departure was clearly so sudden that they left almost their entire household intact, down to cars, clothing, and food in the refrigerator. Most significant, though, investigators had established that several of the men publicly identified as among the 9/11 hijackers, including purported ringleader Mohammed Atta, had visited the house and/or been linked to it through a web of telephone communications.
The FBI told none of this to Congress, and it was not mentioned in the original 9/11 Commission report released in 2004.
See GRAPHIC info here.