SEATAC, Wash. -- An airline employee stole an empty Horizon Air turboprop plane, took off from Seattle-Tacoma International Airport and crashed late Friday, officials said. The Pierce County Sheriff's Office said the man was 29 and "suicidal." The man has been identified as Richard Russell.

Ed Troyer, a spokesman for the Pierce County Sheriff's Department, said on Twitter that preliminary information suggests the crash occurred because the man was "doing stunts in air or lack of flying skills."

There was no connection to terrorism and no others were involved, said Troyer. It was believed the man, whose name was not immediately released, was killed.

Follow this thread for official info. This is not a terrorist incident. Confirmed info .. this is a single suicide male. We know who he is. No others involved. — Pierce Co Sheriff (@PierceSheriff) August 11, 2018

The aircraft was stolen at about 8 p.m. Alaska Airlines said it was in a "maintenance position" and not scheduled for a passenger flight. Horizon Air is part of Alaska Air Group and flies shorter routes throughout the U.S. West.

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Pierce County Sheriff Paul Pastor said the man "did something foolish and may well have paid with his life."

Video showed the Horizon Air Q400 doing large loops and other dangerous maneuvers as the sun set on the Puget Sound. The Q400 is a turboprop aircraft with 76 seats. There were no passengers aboard.

The man could be heard on audio recordings telling air traffic controllers that he is "just a broken guy." An air traffic controller called him "Rich," and tried to convince him to land the airplane.

"There is a runway just off to your right side in about a mile," the controller says, reffering to an airfield at Joint Base Lewis-McChord.

"Oh man. Those guys will rough me up if I try and land there," the man responded, later adding, "This is probably jail time for life, huh?"

"I've got a lot of people that care about me," the man later said. "It's going to disappoint them to hear that I did this...Just a broken guy, got a few screws loose, I guess."

Authorities said the man was a 3.5-year Horizon employee and had clearance to be among aircraft. They also said he didn't have a pilot's license, and that it is unclear how he attained the skills to do loops in the aircraft before crashing about an hour after taking off.

They said he used a machine called a pushback tractor to first maneuver the aircraft so he could board and then take off Friday evening. The man went through various background checks to get clearance to be in the secured area, according to authorities.

The plane crashed on Ketron Island, a small island in the Puget Sound that is home to about two dozen residents.

Witnesses reported seeing the plane being chased by military aircraft before it crashed. Troyer said two F-15 military planes scrambled out of Portland, Oregon, and were in the air "within a few minutes" and the pilots kept "people on the ground safe." He said the military planes were not involved in the crash.

Gary Beck, President and CEO of Horizon Air, said in a statement the plane crashed "about an hour" after it left Sea-Tac airport.

The U.S. Coast Guard sent a 45-foot vessel to the crash scene after witnesses reported seeing a large plume of smoke in the air, Petty Officer Ali Flockerzi said. Video showed fiery flames amidst trees on the island, which is sparsely populated and only accessible by ferry.

Alaska Airlines said no structures on the ground were damaged.