Investigation continues into how man stole, crashed Horizon plane

SEA-TAC AIRPORT, Wash. - The investigation continued Sunday into the man who stole a Horizon plane Friday as family members mourned the loss of the pilot.

Richard Russell stole the Bombardier Q400 plane at Sea-Tac Airport Friday night then crashed on Ketron Island about an hour later, investigators said.

Saturday night, Russell's family called him a faithful husband, loving son and good friend.

In a statement, they called Russell, whose nickname was "Beebo," warm, kind and gentle. They said his death comes as a complete shock.

WATCH: Family of Richard Russell, the 29-year-old man who stole a Horizon Air plane and crashed, speaks out in a heartbreaking interview for the first time.

“A childhood friend remarked that Beebo was loved by everyone because he was kind and gentle to each person he met,” added Mathews.

His former coworkers said he was like a brother.

"He always had a smile on his face, he would joke around I literally can't think about anything bad to say about him he was just an all-around great guy."

The family also thanked the authorities, Alaska Air and the community for their prayers. They are now asking for space to mourn.

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WATCH: Drama in the skies over Puget Sound

WATCH: Daytime aerial photos of the crash scene:

Alaska airlines is working with the Federal Aviation Administration, the Federal Bureau of Investigation, and the National Transportation Safety Board to find out exactly what happened that Friday night. So far, only Russell was aboard the airplane, an employee of Horizon Air, who was operating the aircraft.

“I want to thank the employees of Horizon Air and our guests,” said Gary Beck, President and CEO of Horizon Air. “Our primary objective is to do everything possible to support all of you.”

WATCH: 11 a.m. news briefing

FBI and National Transportation Safety Board investigators plan Saturday to visit the crash site of a stolen Horizon Air passenger plane on Ketron Island near Steilacoom.

Horizon Air said a ground services employee boarded the plane at about 7:30 p.m. Friday night and took off from Sea-Tac Airport. No passengers were on the plane.

Two F-15 jets were scrambled from the 142nd fighter squadron in Portland. As those jets closed on the Horizon turboprop about an hour into the flight, it nose dived and crashed.

Investigators will be looking for the cockpit voice recorder and the data recorder from the plane hoping they will provide new clues about the incident.

"We already have the air traffic and pilot communications, but he might have been talking to himself in the cockpit and they might be able to get some additional information so that's where that's valuable," said NTSB Regional Chief Debra Eckrote.

WATCH: 8:40 a.m. briefing by NTSB Regional Chief Debra Eckrote:

Eckrote said crews will try to recover the body of the pilot. Investigators will also be looking into how an employee could steal a plane and manage to take off at a major airport.

The plane flew very erratically. At one point, the plane turned upside down and dove toward Puget Sound as horrified witnesses watched from the ground. The plane pulled up just above the water.

WATCH: Horizon Air plane goes upside down over Puget Sound

Air traffic controllers were in contact with the pilot during his flight. At times, he sounded distraught.

Pilot: "...just a broken guy. A few screws loose...just now realizing it."

At one point, controllers tried to convince him to land the plane at the McChord runway at Joint Base Lewis-McChord.

Controller: "There is the runway just off to your right side in about a mile. Do you seen that? That's the McChord field."

Pilot: "Oh man, those guys will rough me up if I tried landing there. I think I might mess something up there, too. I wouldn't want to do that. They probably got anti-aircraft!"

Controller: "Nah, they don't have any of that stuff. We're just trying to find a place for you to land safely."

Pilot: "Yeah, I'm not quite ready to bring it down just yet. Holy smokes! I gotta quit looking at the fuel 'cause it's going down quick."

Controller: "If you could, could you start a left hand turn? And we'll take you down to the southeast please."

Pilot: "This is probably jail time for life, huh? I would hope it is for a guy like me."

LISTEN: Air Traffic Control speaks to pilot

WATCH: Witness Brenda Leech describes what she and her family saw from their home in Steilacoom, Wash.

Sea-Tac Airport was shut down during the incident delaying dozens of flights, some for several hours. Operations resumed following the crash.

WATCH: *** VIDEO WARNING**** Explicit language

WATCH: Statement from Horizon Air Chief Operating Officer Constance von Muehlen

Alaska Airlines said the plane involved in the incident is a Bombardier Q400.

That plane is 107 feet nine inches long with a wingspan of 93 feet three inches and a cruising altitude of 25,000 feet. It normally contains 76 seats.

The Q400 has a cruising speed of 414 miles per hour and a crew of two pilots and two flight attendants.

The FBI said it is working with state, local and federal partners to figure out what happened. They did say this was not considered a terrorist threat.

WATCH: KOMO News Breaking News coverage of stolen Horizon Air plane and crash: