Sources: FBI names suspect viewed as key leader

WASHINGTON (CNN) -- The FBI now believes suspected hijacker Abdul Aziz Alomari -- one of the men officials believe was aboard American Airlines Flight 11, which slammed into the north tower of the World Trade Center -- played a "key leadership role" in the September 11 terror attacks, law enforcement sources tell CNN.

The sources told CNN that the FBI gathered evidence such as e-mail messages, phone calls, airplane tickets and contacts made by the suspect before the strikes that indicate Alomari played an important role. At latest count, about 6,500 people are presumed dead in the attacks in New York and Washington.

Alomari is one of two suspected hijackers whose pictures were captured on surveillance cameras at the airport in Portland, Maine, at 5:45 a.m. EDT on September 11, three hours before an American Airlines jet was flown into the Trade Center, demolishing one of the nation's tallest buildings.

In the photographs, Alomari and Mohammed Atta, both carrying black bags, are seen emerging from a security checkpoint, their bags having just been X-rayed. Authorities say they caught a 6 a.m. flight to Boston and boarded the doomed American flight.

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The flight manifest shows Alomari and Atta sat in the business class section of Flight 11. The two, along with other suspected hijackers, are believed to have used box cutters and knives to commandeer the plane; Atta is believed to have been the pilot.

American Airlines Flight 11 was the first of four hijacked airplanes that unleashed that day's horror.

Sources would not elaborate further on the evidence against Alomari, but they called him a "coordinator." One source said Alomari played "a significant role in carrying out the attacks."

Alomari is one of several suspected hijackers who spent time in southern Florida in the months before the attacks.

With the investigation widening, U.S. law enforcement authorities are working to extradite a Yemeni man being held in Toronto, who U.S. officials said was carrying three false Yemeni passports aboard a Germany-to-Chicago flight that was diverted to Canada on the day of the suicide hijackings.

The man, identified by law enforcement officials as Nageeb Abdul Jabar Mohamed Al-Hadi, was detained in Canada within hours of the hijackings, officials said.

Federal agents in Chicago, inspecting Al-Hadi's luggage that arrived on an earlier Lufthansa flight and was not claimed -- found suspicious evidence such as an identification card and a piece of paper sewn into a pants pocket with Arabic writing on it, according to court documents. Authorities also found two Lufthansa crew uniforms in his suitcases.

Al-Hadi was charged in federal court in Chicago with carrying false documents, but authorities did not immediately say what, if any, connection the man may have had with the hijackers.

Justice officials say they know of no established link between Al-Hadi and the hijackers, but U.S. authorities wanted him in custody after finding false passports.

Search warrants executed

In northern Kentucky, six search warrants -- four federal and two state -- were executed as part of the investigation. Spokesman David Beyer also said "numerous" people were interviewed by FBI agents, and 25 were detained on potential immigration violations.

The FBI did not release any details of the warrants, which have been sealed by the court.

In New York, the nation's top two law enforcement officers Friday toured the twisted and smoldering rubble where the twin towers of the World Trade Center once stood.

Attorney General John Ashcroft and FBI Director Robert Mueller praised rescue crews for their tireless efforts in the aftermath of the tragedy and pledged to hunt down those responsible.

"We will bring them to justice or we will take justice to them," Ashcroft said, quoting President Bush speaking in his address to Congress Thursday night.

Both men stressed the United States must remain on heightened alert for more potential terrorist strikes -- or as Ashcroft put it: "The entirety of America (must) recognize we have a vulnerability ... but America cannot yield."

On an overcast day, Ashcroft and Mueller went to ground zero escorted by Gov. George Pataki and Mayor Rudy Giuliani. With the pile of debris in the background and hundreds of rescue crews hard at work, the two struggled for words.

Pointing to the site, Ashcroft was taken aback, saying, "There are workers in the midst of that rubble and my hat goes off to them."

Mueller, visibly shaken, called the obliterated 110-story towers and the ruined remains of numerous other buildings the "unspeakable horror of mass murderers."

"We will not sleep until they are brought to justice," he said.

In other developments:

-- British police are still holding three people arrested in connection with the United States hijack attacks as international efforts began yielding suspects. Three men and one woman were originally arrested, but one of the men was released Saturday. No nationalities were given of those arrested.

-- Also in Europe, French police on Friday detained eight people suspected of belonging to extremist Islamic groups thought to be planning attacks on U.S. interests in France, that nation's Interior Ministry said.

-- In the United States, a federal judge in Detroit, Michigan, denied bail Friday for three men arrested this week in connection with the attacks September on the World Trade Center and the Pentagon.

-- In Boston, Massachusetts, Gov. Jane Swift and Boston Mayor Thomas Menino learned from U.S. Attorney General John Ashcroft that the city could be the site of terrorist strikes in coming days, although Ashcroft stressed that no specific threats had been made.

-- Travel bookings Web sites Travelocity.com and Expedia.com confirmed with CNN on Friday that they have been approached by investigators to provide reservation data.

--CNN Correspondent Susan Candiotti and Justice Producer Terry Frieden contributed to this report.