Former Navy SEAL Matt Bissonnette, writing under the pseudonym Mark Owen in No Easy Day, claims that Osama bin Laden was dead when Navy SEAL’s burst into his bedroom.

The book is to be published next week by Penguin Group (USA)’s Dutton imprint.

Matt 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 Osama 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.

Matt 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 Osama 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.

Former Navy SEAL Matt Bissonnette, writing under the pseudonym Mark Owen in No Easy Day, claims that Osama bin Laden was dead when Navy SEAL’s burst into his bedroom

Osama bin Laden as wearing a white t-shirt, loose-fitting tan pants and a tunic.

In the account related by administration officials after the raid in Pakistan, the SEALs shot Osama 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, September 4, 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 on Tuesday.

The account is sure to again raise questions as to whether the raid was intended to capture or simply to kill bin Laden. Matt 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 Matt Bissonnette, the lawyer said that if Osama bin Laden was “naked with his hands up”, they should not “engage” him. If Osama bin Laden did not pose a threat, they should “detain him”.

In another possibly uncomfortable revelation for U.S. officials who say Osama bin Laden’s body was treated with dignity before being given a full Muslim burial at sea, the author reveals that in the cramped helicopter flight out of the compound, one of the SEALs called “Walt” – one of the pseudonyms the author used for his fellow SEALs – was sitting on bin Laden’s chest as the body lay at the author’s feet in the middle of the cabin, for the short flight to a refueling stop inside Pakistan where a third helicopter was waiting.

This is common practice, as troops sometimes must sit on their own war dead in packed helicopters. Space was cramped because one of the helicopters had crashed in the initial assault, leaving little space for the roughly two dozen commandos in the two aircraft that remained. When the commandos reached the third aircraft, Osama bin Laden’s body was moved to it.

Matt Bissonnette writes disparagingly that none of the SEALs were fans of President Barack Obama and knew that his administration would take credit for ordering the May 2011 raid. One of the SEALs said after the mission that they had just gotten Obama re-elected by carrying out the raid.

But he says they respected him as commander in chief and for giving the operation the go-ahead.

Matt Bissonnette writes less flatteringly of meeting Vice President Joe Biden along with Barack Obama at the headquarters of the 160th Special Operations Aviation Regiment after the raid. He says Joe Biden told “lame jokes” no one understood, reminding him of “someone’s drunken uncle at Christmas dinner”.

Beyond such embarrassing observations, U.S. officials fear the book may include classified information, as it did not undergo the formal review required by the Pentagon for works published by former or current Defense Department employees.

Officials from the Pentagon and the CIA, which commanded the mission, are examining the manuscript for possible disclosure of classified information and could take legal action against the author.

In a statement provided to The Associated Press, the author says he did “not disclose confidential or sensitive information that would compromise national security in any way”.

Matt Bissonnette’s real name was first revealed by Fox News and confirmed to The Associated Press.

Jihadists on al-Qaeda websites have posted purported photos of the author, calling for his murder.