FBI's investigation into 9/11: First document released following Biden's promise to declassify materials

Washington — The FBI on Saturday released the first document related to the 9/11 attacks since President Biden ordered the declassification of more records last week, unveiling a memo detailing "significant logistic support" that two of the Saudi hijackers received in the U.S. 

The document, which is heavily redacted, comes from the secret FBI investigation into 9/11 — dubbed "Operation Encore" — which centered on the two hijackers who lived in San Diego and who may have assisted them.  

The 16-page document is dated April 4, 2016, and describes a November 2015 FBI interview with an unidentified individual related to his pending U.S. citizenship application.

The interview was intended "to ascertain the circumstances of his contact with" people who provided "significant logistic support" to two 9/11 hijackers, Nawaf al-Hazmi and Khalid al-Mihdhar.

One focus was the role of a Saudi national named Omar al-Bayoumi, who had helped the hijackers get settled in San Diego. Bayoumi co-signed their lease on an apartment and helped them open a bank account. 

The 9/11 Commission Report from 2004 had said Bayoumi's initial meeting with the hijackers came through a chance encounter at a restaurant in Los Angeles and that investigators had seen "no credible evidence that he believed in violent extremism or knowingly aided extremist groups."

According to the document released Saturday, Bayoumi had allegedly talked about the need for the Islamic community to "take action" and that they were "at jihad," citing an FBI interview approximately one month after 9/11 with the ex-wife of an unidentified individual who claimed she had met with Bayoumi multiple times.  

Bayoumi is described in the document as having been "treated with great respect" at the Saudi consulate in Los Angeles. He was an employee at a Saudi aviation company, but the document released on Saturday cited witnesses who described him as a "ghost employee" who would not show up for work.

The document also suggested that he planned his initial meeting with the hijackers and that he had multiple phone conversations with the roommate of someone who provided support for Osama bin Laden. 

CBS News has previously reported about a notebook recovered at Bayoumi's home by British police. The notebook had a handwritten drawing of a plane and a mathematical equation that may have been used in preparation for the attack, an assessment that appeared in the sworn declaration of a pilot interviewed by investigators.

The FBI document also mentions other people in the investigation, including Fahad al-Thumairy, who was an imam at the King Fahd Mosque in Los Angeles and an accredited Saudi diplomat at the consulate, according to the 9/11 Commission Report. The Operation Encore document references a call from Thumairy's phone to the home of two men who would later be detained at Guantanamo Bay, and it says that a person whose name is redacted "was tasked by Thumairy to assist Hazmi and Midhar while they were in Los Angeles." 

It cites reporting that Thumairy and another individual used influence with the Saudi government to keep someone employed at the Saudi consulate whom the consulate wanted to fire for distribution of "extremist Muslim literature." And it says Thumairy was in phone contact with suspects connected to al Qaeda and a plot to bomb Los Angeles International Airport. 

According to the 9/11 Commission Report, Thumairy denied "promoting violent jihad." The report concluded, "After exploring the available leads, we have not found evidence that Thumairy provided assistance to the two operatives."

The FBI investigation also looked into assistance for hijackers on the East Coast. The document released Saturday describes a meeting in Falls Church, Virginia, with hijackers and two other individuals that occurred in a "uniquely similar fashion" to the way Bayoumi initially described his first meeting with the hijackers in Los Angeles. 

The declassification is part of a push by families of victims from 9/11 who are suing Saudi Arabia for money and demanding to know if the government provided aid to the hijackers. 

Danny Gonzalez, a former FBI agent who worked on the Encore investigation and is now an investigator for the families, told CBS News that he's confident two of the hijackers had a U.S.-based support network. "Nineteen hijackers cannot commit 3,000 mass murders by themselves," Gonzalez said in his first television interview about the investigation. 

Jim Kreindler, court-appointed co-chair for the plaintiffs, said in a statement that the new document supports their case. "The findings and conclusions in this FBI investigation validate the arguments we have made in the litigation regarding the Saudi government's responsibility for the 9/11 attacks. This document, together with the public evidence gathered to date, provides a blueprint for how al Qaeda operated inside the U.S. with the active, knowing support of the Saudi government." 

Brett Eagleson, whose father Bruce was killed at the World Trade Center, said that the release "accelerates our pursuit of truth and justice against the Kingdom of Saudi Arabia for the worst terrorist attack to occur on U.S. soil."

The Saudi government had no immediate response, but in the past has denied official Saudi government involvement in the 9/11 plot and has supported the release of investigative documents. 

The Saudi embassy in Washington, D.C., issued a statement last week saying "any allegation that Saudi Arabia is complicit in the September 11 attacks is categorically false." It claimed "longstanding support for the full declassification of any documents and materials relating to the United States' investigation of the terrorist attacks, with the hope that a full release of these documents will end the baseless allegations against the Kingdom once and for all."