Al Qaeda Wedding Tape Gives Clues

May 6 -- A videotape obtained by ABCNEWS may offer U.S. authorities clues about the planning of the Sept. 11 terror attacks against the United States and the whereabouts of suspected terrorists still at large.

German officials describe the tape, which shows a wedding celebration at a mosque in Hamburg, Germany, in October 1999, as "the smoking gun" of their investigation into the Hamburg al Qaeda cell responsible for the 9/11 attacks. They say it is crucial evidence in their search for terrorists.

Two weeks after the wedding, at least four members of the Hamburg cell headed to Afghanistan for a final planning session with Osama bin Laden, according to U.S. authorities.

At the wedding, there were no women present, not even the bride.

But among the men present were at least two of the hijack pilots: Marwan Al-Shehhi (before he shaved his beard), who took the controls of United Flight 175, the second plane to hit the World Trade Center in New York; and Ziad Jarrah, who was piloting United Flight 93, the plane that crashed near Shanksville, Pa., when its passengers fought back against the hijackers.

Al-Shehhi and Jarrah, along with other cell members, were brought together because the groom, Said Bahaji, was deeply involved in the plot, according to German authorities, who have charged him with some 3,000 murders in the 9/11 attacks.

Leaving his new wife behind, Bahaji fled to Afghanistan before Sept. 11, 2001, with Zakariya Essabar, who was also charged in the terror attacks in Germany.

Authorities are still trying to identify or locate Bahaji and Essabar, along with many of the wedding guests.

"You have a cell, a nucleus, consistent with al Qaeda methodology: … Are these people — as we sit here today — do they pose a threat, whether it is to the German government or the United States government?" said Jack Cloonan, a former FBI investigator.

Some guests at the wedding have been caught. The principal speaker at the ceremony, Ramzi Binalshibh, who was allegedly the logistics chief of the Sept. 11 plot and is one of the top al Qaeda leaders in U.S. custody, urged guests to fight Jews.