The Pentagon has warned it is considering legal action against the former U.S. commando who has written a first-person account of the raid that killed al-Qaida chief Osama bin Laden.

In a letter to the author Thursday, the Pentagon said he is “in a material breach and violation of the non-disclosure agreements” that he signed as a member of the elite U.S. Navy SEALs force. U.S. defense officials did not clear the book in advance, which opens the possibility that the author could face criminal prosecution.

The upcoming book No Easy Day was written by a 36-year-old SEAL who took part in the raid and penned the book under the pseudonym Mark Owen.

His new first-person account of the raid says the al-Qaida leader was unarmed and shot in a doorway, a different version from the official account of what happened last year in Pakistan.

The Obama administration has maintained that members of the elite SEALs force confronted bin Laden in his bedroom last May and killed him with a shot to the chest and another above the left eye, after assuming that he was reaching for a weapon.

But according to the author, his team first shot bin Laden, even though they could not tell whether he was armed, after seeing him peer out into the hallway as they moved toward the room.

He says they entered the room after shooting the al-Qaida leader and found him twitching on the floor in a pool of blood with two women wailing over his body.

Owen writes that they then moved the women out of the way and shot bin Laden several times in the chest until he was motionless. He says the SEALs later found two unloaded weapons — an AK-47 rifle and a Makarov pistol — in the bedroom.

The book was scheduled to be released on September 11, the anniversary of the al-Qaida terrorist attacks on the United States in 2001. But after some members of the media reported on advance copies they obtained, Owen’s publisher moved the release to September 4.

The White House and a spokesman for the National Security Council have refused to comment on the apparent contradictions between the book’s version of events and the official record.

In addition to the controversy over whether Owen compromised national security, some U.S. media organizations have revealed his true identity. Since then, he has faced death threats posted online.