Around 9:15 p.m. PDT, Alaska Airlines tweeted: "We are aware of an incident involving an unauthorized take-off of a Horizon Air Q400".
"The responding fighter pilots flew alongside the aircraft and were ready to do whatever was needed to protect us, but in the end the man flying the stolen plane crashed on Ketron Island. Was doing stunts in air or lack of flying skills caused crash into Island", the sheriff's office tweeted. This individual who took the aircraft, who has not yet been positively identified until remains are examined, is believed to have been the only person on the plane when the plane was taken from a maintenance position at Sea-Tac. I don't know man!
"What we have is that someone stole a plane from Alaska Airlines", Pierce County Sheriff's spokesman Ed Troyer told the News Tribune.
A witness on the ground, Bryan Sichley, said he was at Chambers Bay in Tacoma and saw a plane nose dive after being chased by two fighter jets.
Horizon Air chief operating officer Constance von Muehlen said the company believed the mechanic involved was a Horizon employee.
"I felt like we were on the ground and we were safe, we weren't in the sky while something was going on", he said after getting off the plane. Preliminary information had suggested it was stolen by a mechanic.
Ketron Island is a privately owned, 221-acre island with a population of 17 people, according to KIRO.
The sheriff's department tweeted that there were no passengers on plane.
No passengers were on board and there were no reports of injuries on the ground.
No passengers were onboard during the incident and normal operations have resumed at the airfield, the airport said on Twitter. He said he didn't see the crash but saw smoke.
Air traffic controllers attempted to talk the man into landing at McChord field - but he refused.
"Rich" said in a matter-of-fact way that he fueled the airplane "to go check out the Olympics", according to audio posted by The Seattle Times newspaper.
Air traffic controllers tried to help the pilot safely land the stolen plane.