(CNN) -- The death of Osama bin Laden does not necessarily mean the death of al Qaeda, the terrorist network he founded, though experts say none of his most likely successors offer the same combination of charisma, cash and credibility among militant Muslims. Bin Laden has long been a prime target for U.S. authorities, a member of the FBI's Ten Most Wanted Fugitives list since 1999 who has had a $25 million bounty on his head since after the September 11, 2001, terrorist attacks. Yet except for a few audiotapes on subjects ranging from climate change to France's role in Afghanistan, he's been relatively quiet in recent years.
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A U.S. official says they know of "no succession plan" now that bin Laden is dead
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An expert says his deputy, Ayman al-Zawahiri, is "not popular with colleagues"
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Another contender is U.S.-born Anwar al-Alwaki, who is now based in Yemen
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Other possibilities are Abu Yahya al-Libi, from Libya, and Ilyas Kashmiri of Pakistan
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