The FBI responded Thursday night to a report that a Boeing 737 was going to be taken over.

The Alaska Air flight, No. 819, was headed to Seattle from Hawaii when it suddenly found a pair of F-15 fighter jets escorting it in from the Pacific. For nearly an hour after receiving a call that a man on the plane was going to hijack it, authorities and the flight crew continued to monitor the alleged suspect on board.

But the FBI says the man identified as the hijacker did not exhibit any stranger behavior and slept most of the flight. He was questioned upon landing at Sea-Tac, but was released. Officials said he was not expected to be arrested. They did not mention what any possible connection was between the caller and the man on the plane.

Passengers were not aware the airliner was being escorted, and other than the presence of additional TSA and security officials near the plane, were not told what happened. The FBI did not say if the caller has been identified or arrested. They are classifying the incident as a hoax.