Al-Yazid is also known as Sheik Said and Abu Saeed al-Masri.
A US official said that word of the al Qaida operative's death is spreading in extremist circles, and that US officials have "strong reason" to believe it's true.
Al-Yazid was the group's prime conduit to Osama bin Laden and Ayman al-Zawahiri, and he was key to day-to-day control, with a hand in everything from finances to operational planning.
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