Story highlights Rob O'Neill said he fired the shot that killed Osama bin Laden in 2011

He was arrested in Butte, Montana

(CNN) Rob O'Neill, the former Navy SEAL who claimed he shot and killed Osama bin Laden, was arrested early Friday in Montana and charged with driving under the influence, authorities said.

"At 2:20 a.m., we responded to a call about someone sleeping [in a vehicle] in the parking lot of a convenience store in Butte," Butte-Silver Bow Undersheriff George Skuletich told CNN. "We woke him up and identified him as Rob O'Neill. He failed a sobriety test and refused a breathalyzer. He was cited with a DUI and has since bonded out of jail."

O'Neill said he expected to be exonerated.

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"The facts are that I took a prescribed sleep aid to help with long-standing severe insomnia," he said. " While the timing was bad and I highly regret this decision, I am innocent of the charges and have entered a plea of not guilty.

"I am confident I will soon be cleared of this matter. I would also like to express my appreciation to the Butte Police Department for their professionalism and courtesy."

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