Update: Authorities on Saturday were seeking clues what drove an airline worker to steal an empty airplane from Seattle’s airport in a security scare that caused the scrambling of U.S. fighter jets and ended when the plane crashed onto a sparsely populated island. According to Reuters, the Federal Aviation Administration, the Federal Bureau of Investigation and the National Transportation Safety Board were investigating the incident.

"We are working closely with the FBI, the NTSB and the FAA to better understand the circumstances of this unauthorized flight," said Alaska Air Group CEO Brad Tilden in a press conference quoted by Alaska Airlines’ Twitter handle.

“We’re working to find out everything we possibly can about what happened,” Tilden said in a statement.

As reported earlier, a Horizon Air ground service agent got into a Bombardier Q400 turboprop aircraft on Friday night in a maintenance area at Seattle-Tacoma International Airport and took off, Horizon sister carrier Alaska Airline said. He flew for about one hour before crashing on Ketron Island in Puget Sound, 25 miles to the southwest.

The 29-year-old man, who has not been named but was identified in tower chatter as "rich", was suicidal and appeared to have acted alone, according to the Pierce County Sheriff’s Department, which said the employee was believed to have been killed in the crash, Reuters reported.

“Doing stunts in air or lack of flying skills caused crash into Island,” the Sheriff’s Department said on Twitter.

In leaked recordings of his conversations with air traffic controllers that were published online, the man said he was sorry to disappoint people who cared about him and described himself as a “broken guy.”

“Got a few screws loose, I guess,” he is heard saying in the recording. “Never really knew it until now.”

I'm listening through the archive of the radio chatter on the #seatac hijacking. Below are some of the clips. pic.twitter.com/ziBAYv7cgn — Jimmy Thomson (@jwsthomson) August 11, 2018

"Until the FBI has the opportunity to get better background on the person, find out what motive they had, it’s a little too early to make a determination on what the objective was,” Debra Eckrote, the NTSB’s western Pacific region chief, said at a news conference.

Two F-15 fighter jets took to the air from a base in Portland, Oregon, and were on the scene within minutes. The jets were armed but did not open fire, North American Aerospace Defense Command spokesman Cameron Hillier said by phone. Instead, the F-15 pilots and air traffic controllers tried to guide the plane west, away from populated areas, said Hillier. No one was hurt on the ground, authorities said.

It was unclear how the employee was able to taxi the plane on a runway and take off without authorization.

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A 29-year-old airline worker at Seattle-Tacoma International Airport hijacked an airplane Friday night, performed aerobatic maneuvers, and then crashed into sparsely populated Ketron Island as two National Guard F-15 fighter jets followed closely behind.

Some dude stole a plane from #Seatac (Allegedly), did a loop-the-loop, ALMOST crashed into #ChambersBay, then crossed in front of our party, chased by fighter jets and subsequently crashed. Weird times. pic.twitter.com/Ra4LcIhwfU — bmbdgty (@drbmbdgty) August 11, 2018

#BREAKING Alaska Airlines says it is aware of an incident involving an unauthorized take-off of a Horizon Air plane from Seattle-Tacoma International Airport. This video was taken by a woman who lives south of the airport. She says this is the plane. (Courtney Jensen Junka) pic.twitter.com/Zh3E4aGfSk — Fox26 News (@KMPHFOX26) August 11, 2018

Seconds after the plan crashed pic.twitter.com/SgxmAr66WG — iRViNGTON BiLLSWORTH 🧜🏿‍♂️ (@iRVvyBaun) August 11, 2018

Apparently someone stole a plane from SeaTac? Saw two fighter jets fly overhead then smoke pic.twitter.com/w0bveGUJQH — McKenna Brown (@mckenna_brown) August 11, 2018

WATCH LIVE: SkyKING over plane crash on Ketron Island. Airport employee stole plane from Sea-Tac and crashed shortly after >> https://t.co/TAFsPYG2Ub pic.twitter.com/57XiUTXzTk — KING 5 News (@KING5Seattle) August 11, 2018

Plane almost belly up, flew straight up then fell straight down, black smoke — Rosie Perpetually Potentially Sensitive (@almostjingo) August 11, 2018

No passengers were aboard the 76-seat Horizon Air Q400 turboprop plane stolen by the ground service agent from Pierce County, as he conducted an "unauthorized takeoff" from the airport.

An airline employee conducted an unauthorized takeoff without passengers at Sea-Tac; aircraft has crashed in south Puget Sound. Normal operations at Sea-Tac Airport have resumed. — Sea-Tac Airport (@SeaTacAirport) August 11, 2018

The airport's tower identified the suspect as "Rich," who crashed on Ketron island in a wooded area, avoiding hitting any structures according to Alaska Airlines.

Okay this insane. A pilot on the plane in front of us just went rogue and took off on an empty plane bypassing orders from the tower. The tower ordered a full stop and they’re trying to communicate with that pilot. Whaaaaaat! — Ben Schaechter (@Bensign) August 11, 2018

The F-15 fighter jets scrambled by the National Guard were flying so quickly that one of them broke the sound barrier, causing a sonic boom that some residents mistook for an explosion, according to the sheriff's department.

Dispelling rumors that the man had been shot down, Washington Governor Jay Inslee said in a statement “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.”

“Those pilots are trained for moments like tonight and showed they are ready and capable,” Inslee said.

During the hijacking, the pilot can be heard communicating with air traffic control as recorded by Twitter user Jimmy Thomson (@jwsthomson).

"I've got a lot of people that care about me," said the man. "It's going to disappoint them to hear that I did this. I would like to apologize to each and every one of them. Just a broken guy, got a few screws loose I guess. Never really knew it, until now."

In another segment, an air traffic control operator tells another individual "Right now he's just flying around, and he just needs some help controlling the aircraft," to which the man interjected "Nah, I mean, I don't need that much help; I've played some video games before." (Full audio here)

I'm listening through the archive of the radio chatter on the #seatac hijacking. Below are some of the clips. pic.twitter.com/ziBAYv7cgn — Jimmy Thomson (@jwsthomson) August 11, 2018

Here he is realizing how quickly he is burning through fuel. pic.twitter.com/ftnpowm9D4 — Jimmy Thomson (@jwsthomson) August 11, 2018

Here, the air traffic controller is trying to talk him into landing. pic.twitter.com/OxEe5T6JHJ — Jimmy Thomson (@jwsthomson) August 11, 2018

Looks like that didn't upload correctly. Here is the clip of him asking for help getting the cabin pressurized so he isn't "so lightheaded." pic.twitter.com/3uDKPKGvHo — Jimmy Thomson (@jwsthomson) August 11, 2018

The man then says "Ah, minimum wage. We'll just chalk it up to that. Maybe that will grease the gears a little bit with the higher-ups."

This clip appears to be just a fragment of a conversation that was stepped on by other traffic, but he is saying something about "chalking it up" to minimum wage. pic.twitter.com/clkUp69A0D — Jimmy Thomson (@jwsthomson) August 11, 2018

“This is probably jail time for life, huh?” said the man. “I would hope it is for a guy like me.”

“Oh, Richard,” said an air-traffic controller, “We’re not going to worry or think about that. But could you start a left turn please?”

At another point, the man says "I'm gonna land it, in a safe kind of manner. I think I'm gonna try to do a barrel roll, and if that goes good, I'm just gonna nose down and call it a night."

The Pierce County Sheriff’s Office directed inquiries to the Federal Bureau of Investigation, indicating federal law enforcement officials will be taking a primary role in the investigation into how the tragic heist unfolded. The plane had been in a “maintenance position” and was not scheduled for passenger flight when it was stolen, according to a statement from Alaska Airlines. “Our hearts are with the family of the individual on board as well as all our Alaska Air and Horizon Air employees,” Horizon Air Chief Operating Officer Constance von Muehlen said in a video statement. -LA Times

According to a job posting on Horizon Air's website, ground service agents "play a critical role to keep our flights running smoothly and safely. Whatever the weather, you'll direct aircraft for takeoff, gate approach, load and unload luggage, and operate equipment to de-ice planes in the winter. "