Navy SEAL Who Claimed to Kill Bin Laden Arrested for DUI

— -- A former Navy SEAL who claimed to fire the shots that killed Osama bin Laden appeared "very confused at the scene" when he was arrested for DUI after being found asleep in his car, an official said today.

When authorities in Montana responded to a complaint of a man passed out in a car in a parking lot early Friday, they found former Navy SEAL Rob O'Neill. They woke him up and noted that O'Neill seemed "impaired," Butte-Silver Bow County Undersheriff George Skuletich told ABC News today.

O'Neill appeared to be "very confused at the scene," Skuletich said. "He seemed like he was under the influence of something."

Skuletich said O'Neill failed a sobriety test at the scene and refused to take any more DUI tests. Skuletich said O'Neill failed a second field sobriety test at the local jail.

O'Neill was booked for DUI early Friday, jail records show. He was released Friday after posting a $685 bond.

O'Neill said he wasn't intoxicated but that he did take a prescribed sleep aid to help with severe insomnia, according to a statement released Friday through a public relations firm, The Associated Press reported.

"While the timing was bad and I highly regret this decision, I am innocent of the charge and have entered a plea of not guilty," his statement said, according to the AP.

O'Neill's representative did not immediately reply to a request for comment from ABC News.

Montana State University said today that O'Neill's scheduled speaking appearance at the school on Monday, April 11, is now cancelled.

"The university is canceling the appearance because of unforeseen circumstances and will be offering a full refund to ticket holders," the statement said. "MSU recognizes the incredible risks Mr. O'Neill undertook in his military career for the benefit of our country and thanks him for his service."

Skuletich said O'Neill is expected to appear in court Monday or Tuesday.

O'Neill has claimed to have been the Navy SEAL that fired the deadly shots that killed bin Laden in the May 2, 2011 operation in Pakistan. Pentagon officials previously said it was unclear whose shots killed bin Laden, according to The AP.