A first-hand account of the Navy SEAL raid that killed Osama bin Laden contradicts previous accounts by U.S. administration officials, raising questions as to whether the al-Qaeda leader presented a clear threat when SEALs first fired upon him.

Bin Laden apparently was hit in the head when he looked out of his bedroom door into the top-floor hallway of his compound as SEALs rushed up a narrow stairwell in his direction, according to former Navy SEAL Matt Bissonnette, writing under the pseudonym Mark Owen, in No Easy Day. The book is to be published next week by Penguin Group (USA)'s Dutton imprint.

Bissonnette says he was directly behind a "point man" going up the stairs in the pitch black hallway. "Less than five steps" from top of the stairs, he heard "suppressed" gunfire: "BOP. BOP." The point man had seen a "man peeking out of the door" on the right side of the hallway.

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