Updated

The FBI long has contended that not a single Al Qaeda (search) operative in the United States collaborated with the 19 hijackers in the Sept. 11 attacks. Yet the commission investigating the attacks has identified two Muslim men who may have had advance knowledge of the plot.

The commission found that two hijackers got substantial help from Mohdar Abdullah (search) and Anwar Aulaqi (search) after settling in California in 2000. The bipartisan panel created by Congress said it cannot discount the possibility the men knew the hijackers' plans.

Abdullah, who recently was deported to Yemen (search), helped the hijackers get driver's licenses. He bragged, while in U.S. custody after the hijackings, that he had known the attacks were coming.

Aulaqi, a cleric who left the United States shortly after Sept. 11, 2001, introduced the two hijackers, Nawaf al-Hazmi (search) and Khalid al-Mihdhar (search), to other people who helped provide living arrangements in this country.

The previously undisclosed information about Abdullah and Aulaqi was contained in one of the commission reports released this month.

The FBI is seeking to find and interview Aulaqi about his contacts with al-Hazmi and al-Mihdhar. It is unclear if U.S. officials know where Aulaqi is.

FBI spokesman Mike Kortan said the Sept. 11 investigation is "ongoing and active" and that any new evidence will be examined closely.

A congressional investigation has concluded that the discovery of al-Hazmi and al-Mihdhar in the United States probably represented the best chance for the FBI and CIA to disrupt the plot.

Both were known to the CIA because of connections to the October 2000 terrorist bombing of the USS Cole (search) in Yemen that killed 17 U.S. sailors. Both had contacts with a longtime FBI informant.

FBI agents were searching for them in the weeks before the attacks because their names were on terrorism watch lists.

Al-Hazmi and al-Mihdhar were among the first four Al Qaeda members chosen in 1999 by Usama bin Laden (search) for the hijacking plot proposed by Khalid Shaikh Mohammed, or KSM, the Sept. 11 mastermind now in U.S. custody.

Much of the commission report is derived from classified interrogations of Mohammed and another senior Al Qaeda planner also in custody -- Ramzi Binalshibh (search).

In general, the 19 hijackers were told to blend in while in the United States by avoiding mosques and fellow Islamic extremists. But al-Hazmi and al-Mihdhar were different.

"Recognizing that neither Hazmi nor Mihdhar spoke English or was familiar with Western culture, KSM instructed these operatives to seek help from the local Muslim community," the report said.

Mohammed told the men to settle in San Diego. So they went there in February 2000 from Los Angeles with help from Omar al-Bayoumi (search), a Saudi who had an apartment complex there. Although Bayoumi helped the hijackers settle in San Diego, there is no evidence he knew they were terrorists, investigators say.

Al-Hazmi and al-Mihdhar made friends in San Diego with some foreign students at the Rabat Mosque (search) in suburban La Mesa. One was Mohdar Abdullah, who the report said was among those students who "appear to have held extremist sympathies."

Abdullah helped al-Hazmi and al-Mihdhar get driver's licenses and enroll in schools in California. Shortly after the attacks, Abdullah told FBI agents in an interview he knew nothing about the plot.

But later, while held on immigration charges, Abdullah bragged to follow inmates that he had advance knowledge of the Sept. 11 mission and even had instructions to pick up plot operatives at Los Angeles International Airport before the attacks, according to the commission's report.

A fellow inmate wrote the Homeland Security Department last spring about Abdullah's claim, according to Jacqueline Maguire, an FBI agent working on the Sept. 11 investigation.

The FBI could not corroborate the inmate's story, she told the commission during its public hearing two weeks ago.

"Another inmate gave another story and the details differed quite significantly," Maguire said.

Ultimately, the FBI chose not to seek criminal charges against Abdullah. The bureau did have Abdullah deported to Yemen in May. Maguire said the CIA was aware of the decision and knows he is in Yemen.

According to the commission report, Al-Hazmi and al-Mihdhar also established a relationship with Aulaqi, an imam at the Rabat Mosque. Aulaqi later moved to Virginia and worshipped at the Dar al-Hijra (search) mosque in Falls Church, Va. Early in 2001, al-Hazmi and al-Mihdhar drove across the country, settled in Alexandria, Va., and began attending Dar al-Hijra.

The commission report cited information that Aulaqi had "extremist ties, and the circumstances surrounding his relationship with the hijackers remains suspicious. However, we have not uncovered evidence that he associated with the hijackers knowing they were terrorists."

At the Falls Church mosque, the imam introduced the hijackers to a Jordanian, Eyad al Rababah, who helped them find an apartment.

In May 2001, al Rababah suggested that al-Hazmi and al-Mihdhar move with him to Fairfield, Conn. The three eventually traveled to Paterson, N.J., where they rented an apartment with two other Al Qaeda operatives.

The commission report said that despite this assistance, there is "insufficient basis" to conclude that Rababah knew that al-Hazmi and al-Mihdhar were terrorists.

While al-Hazmi and al-Mihdhar did not succeed in their original mission -- to learn English and become pilots -- they were part of the team that commandeered the plane that crashed into the Pentagon on Sept. 11.