WASHINGTON, USA (AP) — A firsthand account of the Navy SEAL raid that killed Osama bin Laden contradicts previous accounts by administration officials, raising questions as to whether the terror mastermind 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.

The author writes that bin Laden ducked back into his bedroom and the SEALs followed, only to find the terrorist crumpled on the floor in a pool of blood with a hole visible on the right side of his head and two women wailing over his body.

Bissonnette says the point man pulled the two women out of the way and shoved them into a corner and he and the other SEALs trained their guns' laser sites on bin Laden's still-twitching body, shooting him several times until he lay motionless. The SEALs later found two weapons stored by the doorway, untouched, the author said.

In the account related by administration officials after the raid in Pakistan, the SEALs shot bin Laden only after he ducked back into the bedroom because they assumed he might be reaching for a weapon.

White House spokesman Tommy Vietor would not comment on the apparent contradiction late Tuesday. But he said in an email, "As President Obama said on the night that justice was brought to Osama bin Laden, 'We give thanks for the men who carried out this operation, for they exemplify the professionalism, patriotism and unparalleled courage of those who serve our country.'"

"No Easy Day" was due out September 11, but Dutton announced the book would be available a week early, because of a surge of orders due to advance publicity that drove the book to the top of the Amazon.com and Barnes & Noble.com best-seller lists.

The Associated Press purchased a copy of the book Tuesday.

The account is sure to again raise questions as to whether the raid was intended to capture or simply to kill bin Laden. Bissonette writes that during a pre-raid briefing, a lawyer from "either" the White House or Defense Department told them that they were not on an assassination mission. According to Bissonnette, the lawyer said that if bin Laden was "naked with his hands up," they should not "engage" him. If bin Laden did not pose a threat, they should "detain him."