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Notebook tied to associate of 9/11 hijackers said to contain plane drawing, flight calculations

Two decades after the 9/11 terrorist attacks, a new two-page declaration has become part of both the ongoing litigation by the families of 9/11 victims against the Kingdom of Saudi Arabia and their effort to declassify the underlying FBI records that may show any possible Saudi government officials' assistance to the hijackers prior to September 11, 2001.

The FBI twice quizzed an American pilot in 2012 about a notebook recovered from the home of a close associate of two 9/11 hijackers. The notebook contained a handwritten drawing of a plane and mathematical equation that might be used to view a target and then calculate the rate of descent to the target, according to a sworn declaration expected to be filed soon in federal court and obtained by CBS News. 

"I shared with the FBI my opinion that there was a reasonable basis to believe that the drawing and equation were used as part of the preparations of the al Qaeda terrorists to carry out the 9/11 attacks," Navy veteran and pilot Robert M. Brown wrote. 

In the June declaration, Brown said investigators first questioned him in 2012, recalling that they told him the notebook had been seized by British police in a raid on the home of Omar al Bayoumi, a Saudi national. The 9/11 Commission Report said that Bayoumi helped the first two hijackers to arrive in the U.S. in January 2000, Nawaf al-Hazmi and Khalid al-Mihdhar, get settled in San Diego. 

According to the 9/11 Commission Report, investigators said Bayoumi told them that it was a chance meeting in February 2000 at a Middle Eastern restaurant in Los Angeles that brought him together with the two hijackers. He ended up helping the Saudis — who spoke little English and had little experience in the West  — find an apartment in San Diego. Bayoumi also co-signed their lease and helped them a open bank account. 

The 9/11 Commission Report also found that once the hijackers were settled in San Diego, Bayoumi held a party at their apartment and had an associate videotape the gathering.

According to lawyers for the 9/11 families, Bayoumi was among a group of Saudis, including a former embassy employee, who were recently deposed about possible assistance to the hijackers.  The depositions are under seal.

The Commission which completed its work in 2004, described Bayoumi, who was 42 years old when he met the hijackers, as "a business student, supported by a private contractor for the Saudi Civil Aviation Authority" and concluded he was an "unlikely candidate for clandestine involvement with Islamist extremists." The commission's report described Bayoumi as a "devout Muslim" and "gregarious." It also stated their investigators had seen "no credible evidence that he believed in violent extremism or knowingly aided extremist groups."

Heavily redacted FBI interview summaries from 2003 show Bayoumi told investigators "he just happened to meet them (the two hijackers) in the (Los Angeles) restaurant," and while he did help them get settled, the men moved, and Bayoumi apparently lost track of them. The Kingdom of Saudi Arabia has denied aiding the 9/11 plot, citing the 9/11 Commission findings.

However, after the 9/11 Commission finished its probe, another secret FBI investigation into the Saudi hijackers' time in San Diego was opened. Dubbed "Operation Encore," it further investigated Bayoumi and his contacts with the two hijackers, in addition to Saudi government employees. The 9/11 families want the probe's findings and underlying records publicly released.

In the declaration, Brown said the FBI and New York city police detectives, in their first interview with him, sought information from Brown about his experience as a pilot for American Airlines. They also asked him about his "prior experiences as a pilot of American flight 77 that was operated from Washington (IAD) to Los Angeles (LAX), the same flight hijacked by al Qaeda terrorists on September 11, 2001 and flown into the Pentagon."  

Brown said several months later he spoke with the FBI again. This time, he said that "agents showed and discussed with me a copy of a handwritten drawing (which included an airplane) and equation, and asked me questions about the drawing and equation." 

After reviewing the materials, Brown said that he concluded "the drawing and equation were to calculate the altitude of an aircraft necessary" to see a target on the horizon at 50 and at 70 miles away, and "the equation, together with airspeed, could be used to provide a rough but sufficient means to calculate the rate of descent for an aircraft to fly towards the target." 

Both the FBI and Justice Department declined to comment to CBS News' questions about the accuracy of the declaration, description of the notebook contents, and connection to "Operation Encore." The Justice Department cited ongoing litigation. CBS News was told the FBI interview of Brown was part of that case and reached out to Brown for further comment. A relative declined on his behalf, citing a recent medical issue and asked for privacy.

Tim Frolich, a party to the 9/11 lawsuit against Saudi Arabia, said, "After 20 years, why are there still secrets regarding these documents? It's clear that our government is protecting the Kingdom of Saudi Arabia rather than providing justice for its citizens. We hope that President Biden recognizes the injustice." 

Successive administrations have withheld the records, citing national security. Last year, then-Attorney General Bill Barr invoked the state secrets privilege, stating the materials must remain secret to protect sensitive information, sources and methods. 

President Biden recently ordered the Justice Department to further review the materials for public release. The 9/11 Commission, which concluded more than 15 years ago, found "no evidence that the Saudi government as an institution or senior Saudi officials individually funded the organization. (This conclusion does not exclude the likelihood that charities with significant Saudi government sponsorship diverted funds to al Qaeda.)" 

CBS News provided a series of questions to the media office for the Kingdom of Saudi Arabia in Washington, D.C., concerning whether the notebook was Bayoumi's or whether it belonged to a third party, and if the declaration accurately reflected its contents. The media office said they would review our questions. No immediate comment was provided.

Andres Triay contributed to this report.

Read the full declaration here:

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