WOODBURY - ? Officials say all eyes are on al-Qaida?s number two man Aman al-Zawahiri after the death of Osama bin Laden.

The 59-year-old Egyptian was named by the U.S. in 2009 as al-Qaida?s chief commander and operations and strategic leader. U.S. intelligence officials believe al-Qaida will have a hard time recovering from the death of its leader.

Experts believe bin Laden was just a symbol and that the greatest terrorist threat to the U.S. is al-Qaida in Yemen.

The group almost took down a U.S.-bound airliner on Christmas in 2009. Umar Farouk Abdul-Mutallab allegedly tried to use a bomb hidden in his underwear to blow up Northwest Airlines Flight 253.

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