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ISIS leader confirmed killed by U.S. forces

A U.S. official confirms that Fathi ben Awn ben Jildi Murad al Tunisi - who also went by any of several aliases, including Abu Sayyaf - is the legal name of the ISIS leader killed by U.S. forces in a weekend raid in Syria.

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The intelligence recovered from the operation has been described as substantial. The U.S. is also getting more information from its interrogation of Abu Sayyaf's widow, Umm Sayyaf, who is an Iraqi citizen and is believed to have been an officer herself within ISIS - not just the spouse of the man who was the chief financial officer for ISIS. The U.S. is very interested in what she knows about ISIS hostages, including - but not limited to - the American hostage Kayla Mueller.

Umm Sayyaf is being held in U.S. custody in Iraq and is being interrogated by U.S. forces. CBS News has learned that she has operational knowledge of ISIS.

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U.S. officials have pushed back against the idea that Abu Sayyaf was a "small fish." That criticism has been leveled in part because he did not have a profile high enough to be sanctioned by the U.S. State Department as a terrorist, nor was he on the FBI's Rewards for Justice wanted list. However, a U.S. official said that U.S. intelligence has been tracking him for awhile and that there had been months of advance planning to carry out this raid.