Sheriff's department officials said they were working to conduct a background investigation on the Pierce County resident.
The 29-year-old man, who has not been identified, was suicidal and appeared to have acted alone, the Pierce County Sheriff's Department said on Twitter, adding the employee was probably killed in the crash.
The incident, which the FBI's Seattle office did not consider terrorism, raises questions about airport security. Confirmed info. this is a single suicide male.
The family of an airport ground service agent who stole a passenger plane in the United States, performed some wonderful stunts and then crashed it, taking his own life, are stunned and heartbroken. While Russell was in the air performing hard maneuvers in the air Amy Leddy says her Alaska Airlines flight and the flights of hundreds of other passengers were delayed.
Federal authorities were searching on Saturday for what drove an airline worker to steal an empty airplane from Seattle's airport and crashing it into a nearby sparsely populated island, sparking a security scare that saw USA fighter jets scrambled. The aircraft's unpredictable flight pattern terrified onlookers, who got photo and video footage of the plane's ill-fated excursion.
Audio exchanges between an air traffic controller and the pilot have been released. No one was hurt on the ground, authorities said.
Later Russell said: "I've got a lot of people that care about me".
Royal King told the Seattle Times he was photographing a wedding when he saw a plane and two F-15 fighter jets trailing it. On Friday around 7:32 p.m., he got in the cockpit of an empty 76-seat Horizon Air turboprop plane and took off without authorization.
Alaska Airlines and Horizon Air officials said they were still working closely with authorities to investigate what happened.
Ms Morse's mother, who lives closer to the area where the plane went down, said her whole house shook.
Witnesses described seeing the aircraft performing barrel rolls and loop-the-loops as the military planes directed it away from highly-populated areas and towards Ketron Island.
The aircraft eventually crashed into a small island off the coast of the Puget Sound, sending a plume of fire and smoke into the air and prompting the Coast Guard to deploy a vessel to the scene of the crash, Petty Officer Ali Flockerzi told the Associated Press on Saturday. Only the unknown pilot was on the plane.
"Dozens of personnel were out at the crash site, and co-workers and family members were being interviewed", he said.
One witness filmed the plane doing a large loop-the-loop, which they first thought was part of an air show rehearsal.
How major U.S. stock indexes fared Friday
Declining issues outnumbered advancing ones on the NYSE by a 1.04-to-1 ratio; on Nasdaq, a 1.10-to-1 ratio favored advancers. Shares in leading U.S. banks also plunged significantly with Bank of America, Goldman Sachs, Morgan Stanley, and J.P.
Team gives medication to sick killer whale at sea
Scientists had no plans to take the calf away from J35 or her pod, noting the "tight bond, "reports The Seattle Times ". A team of whale experts has injected an ailing killer whale with antibiotics in a rare effort to save her.
Unai Emery names five Arsenal captains
Another starter who might not make the XI is Aaron Ramsey who suffered a calf injury in pre-season. And stopping Manchester City superstar Sergio Aguero could be an ideal way to silence his critics.