Former soldier claims Osama bin Laden was unarmed and already dead or dying when Navy Seals burst into room and shot him

A US Navy Seal who took part in the raid in which Osama bin Laden was killed has revealed that the former al-Qa'ida leader was unarmed and already dead or dying when soldiers burst into his room.

Written anonymously and published under the name Mark Owen, 'No Easy Day: The Autobiography of a Navy Seal' contradicts many other accounts of the raid which said bin Laden had a weapon and was resisting arrest when soldiers entered the room.

The book also appears to suggest the Seals went against mission orders not to ‘assassinate’ bin Laden if he wasn’t posing a threat.

In a copy of the book, obtained in a shop by The Huffington Post in advance of its release, Owen describes how the Seals saw a man poke his head out of a doorway as they were ascending a narrow staircase.

He writes: “We were less than five steps from getting to the top when I heard suppressed shots. BOP. BOP…I couldn't tell from my position if the rounds hit the target or not. The man disappeared into the dark room.”

The Seals took their time entering the room, but upon doing so they encountered a women wailing over bin Laden’s body.

“Blood and brains spilled out of the side of his skull” and he was still twitching and convulsing, Owen writes. While bin Laden lay dead or dying, Owen writes that he and another Seal “trained our lasers on his chest and fired several rounds. The bullets tore into him, slamming his body into the floor until he was motionless.”

After repeat attempts to identify the man, the Seals interrogated a young girl and a woman, who confirmed he was Osama bin Laden.

Later, as they searched bin Laden’s room, the Seals found two guns - an AK-47 and a Makarov pistol – but both were unloaded, suggesting bin Laden was in no way ready to put up a defence.

Owen goes on to criticise inaccurate accounts of the raid, which he describes as being reported “like a bad action movie”. He also rules out reports that Seals were fired upon as they arrived at the gates of bin Laden’s compound, and dismisses talk of a 40-minute fire-fight between the Seals and Osama bin Laden’s guards.

Owen’s account seems to suggest that the Seals were not under immediate threat when they killed bin Laden. This would appear to contradict the instructions given to them by commanders when they were briefed on their mission.

During a meeting with top commanders, a lawyer from either the Pentagon or the White House “made it clear that this wasn't an assassination,” writes Owen, who recounted the instructions: “I am not going to tell you how to do your job. What we're saying is if he does not pose a threat, you will detain him.”

Although the book is one of the most hotly-anticipated releases this year, the ‘anonymous’ author appears to be coming in for unwanted personal attention.

Not long after the announcement of the book, FoxNews.com identified the soldier as a 36-year-old who retired from service shortly after the bin Laden raid.

Last week an official al-Qa'ida website posted a photograph and the name of a former Navy commando they claim is responsible for the book, calling him 'the dog who murdered the martyr Sheikh Osama bin Laden.'

It was followed by comments that called for the man's death, including one response that said, 'O' Allah, kill every one of them,' and another that said, 'O' Allah, make an example of him for the whole world and give him dark days ahead.'

Meanwhile the head of US Special Operations Command told current and former troops that the military would take legal action against anyone exposing sensitive information that could harm fellow forces.

In an open, unclassified letter emailed to the active-duty special operations community, Admiral Bill McRaven wrote: 'We will pursue every option available to hold members accountable, including criminal prosecution where appropriate.”