A “suicidal” airline mechanic stole an empty Horizon Airlines plane, took off from Sea-Tac International Airport and was chased by military jets before crashing near a small island in the Puget Sound on Friday night, officials said.

Preliminary information suggests that the 29-year-old mechanic stole the Horizon Air Q400 and the crash occurred because he was “doing stunts in air or lack of flying skills,” the Pierce County Sheriff’s Department said.

Ed Troyer, a spokesman for the Pierce County Sheriff’s Department, said on Twitter the man was suicidal and there was no connection to terrorism.

Video showed the aircraft doing large loops and other dangerous maneuvers as the sun set.

Witnesses reported seeing the plane being chased by military aircraft before it crashed near Ketron Island, southwest of Tacoma, Washington. There were no passengers aboard. Troyer said F-15 aircraft were in the air “within a few minutes” and the pilots kept “people on the ground safe.”

The sheriff’s department said they were working to conduct a background investigation on the Pierce County resident, whose name was not immediately released.

The man could be heard on audio recordings telling air traffic controllers that he is “just a broken guy.”

The U.S. Coast Guard was sending a 45-foot (14-meter) vessel to the crash scene after witnesses reported seeing a large plume of smoke in the air, Petty Officer Ali Flockerzi said. The man’s condition wasn’t immediately known.

Royal King told The Seattle Times he was photographing a wedding when he saw the low-flying turboprop being chased by to F-15s. He said he didn’t see the crash but saw smoke.

“It was unfathomable, it was something out of a movie,” he told the newspaper. “The smoke lingered. You could still hear the F-15s, which were flying low.”

Horizon Air is part of Alaska Air Group and flies shorter routes throughout the U.S. West. The Q400 ix a turboprop aircraft with 76 seats.

Spokesmen for the Transportation Security Administration, the U.S. Department of Homeland Security and the Federal Aviation Administration directed inquiries to local authorities.