PORTLAND, Maine (AP) — The lawyer for a Florida man accused of causing a trans-Atlantic flight to be diverted to Maine is exploring the man’s possible use of Ambien but said it’s too early to say whether the sleep aid, or something else, caused his bizarre actions.

Derek Stansberry’s behavior on the Paris-to-Atlanta flight was out of character, based on everything that has come to light so far, said defense lawyer Virginia Villa.

The former Air Force intelligence specialist handed a rambling note to flight attendants that said his passport was fake and then told an air marshal that he had dynamite, according to court documents. He later told investigators it was a ruse to deflect attention because he possessed “classified information.”

Stansberry, 26, of Riverview, Fla., was on the April 27 flight while returning from his work for a defense contractor in the African nation of Burkina Faso. He was supposed to come home a week earlier, but his return was delayed by volcanic ash that shut down air travel over Europe, said his father, Richard Stansberry.

Richard Stansberry said his son had a prescription for Ambien, which is commonly used by travelers to sleep on long flights. His son indicated he took an Ambien earlier in the day, before the incident unfolded over the Atlantic. He also told an air marshal he took eight pills.

Some of Ambien’s rare side effects include confusion, agitation and hallucinations, according to the Food and Drug Administration.

“Ambien may be able to explain those very odd sequence of statements and events that have been reported. It may not,” Villa said from her office in Bangor. She said she’s keeping an open mind.

For now, Stansberry is being detained in Maine on charges of making false information and threats, and interfering with a flight crew. A competency examination has been ordered.

In a note peppered with military jargon, Stansberry claimed his passport and identity were fake, that he purchased a bag on eBay, that he “screwed up” and that he would leave his fate to the “HN,” or host nation. He also said he’d illegally visited “Ouaga,” which may be short for Ouagadougou, the capital of Burkina Faso.

Next, Stansberry told a federal air marshal that he had dynamite and a detonator in boots in his carry-on bag, according to court documents. After the plane landed, he told investigators that passengers were ridiculing him and using “round robin” interrogation techniques on him; he said he concocted the story about dynamite “to divert attention from the fact that he had classified information.”

Before leaving the Air Force last year, Stansberry held a top security clearance while working for the 4th Special Operations Squadron known as the “Ghostriders,” which flies the AC-130 gunship, said Capt. Lisa Citino, spokeswoman for the 1st Special Operations Wing at Hurlburt Field, Fla.

In Africa, Stansberry was employed by Eatontown, N.J.-based R4 Inc. and was performing military-to-military cooperation activities in Burkina Faso, said Nicole Dalrymple, spokeswoman for the U.S. Africa Command.

The company declined to comment.

Richard Stansberry said the accusations are “totally out of character” for his son, who passed background checks for his security clearance and received an honorable discharge after four years in the Air Force. Before the episode, Derek Stansberry had been looking forward to returning home to see his girlfriend and to work on his house.

The father, who lives in Apollo, Fla., said he doesn’t know what caused his son’s erratic behavior.

“His record growing up was squeaky clean. His military career was squeaky clean. And ever since he got out of the military it was the same,” Richard Stansberry said.