Since former U.S. Navy SEAL Robert O'Neill identified himself as the man who killed Osama bin Laden in an interview with the Washington Post, there have been competing narratives from members of the elite fighting unit about which of them actually killed the al Qaeda leader. O'Neill was arrested for driving under the influence Friday, April 8, 2016. Getty Images

Former Navy SEAL Robert O'Neill, who publicly identified himself as the man who shot Osama bin Laden, is under investigation following an allegation that he may have leaked classified information to those not authorized to receive it, media reports said Tuesday. O’Neill revealed in November that two other SEALS had also fired shots at the al Qaeda leader during the raid on his Abbottabad, Pakistan, hideout in 2011.

O’Neill reportedly gave several interviews after coming forward about his role in the operation that led to bin Laden's death. Last month, O’Neill told The Associated Press (AP) that he was careful not to disclose classified information about the operation while speaking publicly about it.

"The Naval Criminal Investigative Service (NCIS) is in receipt of an allegation that Mr. O'Neill may have revealed classified information to persons not authorized to receive such information,” Cdr. Ryan Perry, a Navy spokesman, said Tuesday, according to AP. “In response, NCIS has initiated an investigation to determine the merit of the allegations."

However, it was unclear to whom O’Neill had allegedly disclosed the classified information, or what the information was, according to The Daily Beast.

O’Neill’s revelations were contradictory to that of another former SEAL Matt Bissonnette, who wrote in his book, “No Easy Day,” under the pseudonym Mark Owen, that the man who led the way to bin Laden's bedroom fired the fatal shot. He said that a second SEAL, presumably O’Neill, fired a second round.

“Two different people telling two different stories for two different reasons,” Bissonnette had reportedly said. “Whatever he says, he says. I don’t want to touch that.”

Pentagon officials have reportedly said that it is unclear whose shots actually killed bin Laden.