"Acted alone he is 29-year-old Pierce county residence [sic]", the department tweeted.
"Apparently this was a plane that was stolen from SeaTac Airport".
Mr Russell, 29, who authorities say was suicidal and did not have a pilot's licence, died after the plane plummeted into a small island yesterday.
Video from a witness on the ground shows the plane at one point doing a loop, putting the aircraft upside-down, then pulling up just feet above a body of water. Two f-15 fighter jets were scrambled from Portland to intercept the stolen aircraft.
Alaska Airlines confirmed there was an "unauthorized take-off" of a Horizon Air plane from Sea-Tac airport around 9.50 p.m Friday evening (04:50 Saturday UTC).
"In this season of life, we enjoy exploring as much as possible, whether its a day (or so) trip to one of Alaska Airline's destinations or visiting a new area of Washington", he wrote. Terrorism was quickly ruled out as a motive, but the incident still led to a complete shutdown of air traffic in and out of Sea-Tac airport. We know who he is.
Pierce County Sheriff Paul Pastor said the man "did something foolish and may well have paid with his life", according to the AP.
Video showed the Horizon Air Q400 doing large loops and other risky manoeuvres as the sun set on Puget Sound. There were no passengers aboard.
An airline employee allegedly hijacked a plane at the Seattle-Tacoma International Airport on Friday night right before it crashed into the Puget Sound in Washington. It normally carries 76 passengers.
Mr Southers said the man could have caused mass destruction.
As two fighter pilots flew behind and closed in on the Q400, Richard crash-landed the plane in a cloud of smoke.
We would like to thank the authorities who have been both helpful and respectful, Alaskaair for their resources, the community, his friends and his family for their incredible support and compassion, and Jesus whose steadfast love endures. They pursued the aircraft before it went down on Ketron Island, between Tacoma and Olympia.
Hurricane Hector is coming to Hawaii
The strongest winds are expected down the slope of the mountains, across elevated terrain, over headlands, and through gaps". A high surf warning has been issued for east shores of the Big Island in anticipation of the impacts of Hurricane Hector .
The sheriff's department said they were working to conduct a background investigation on the man, whose name was not immediately released.
Authorities said the man was a Horizon employee for three and one-half years, had clearance to be among aircraft, and was a Horizon Air ground service agent.
In audio recordings posted on Broadcastify, the man can be heard talking to air traffic controllers as they try to guide him to land the plane.
Communication between Russell and air traffic controllers revealed a conversation between authorities and Rich, who boisterously says he fueled the plane "to go check out the Olympics [mountains]".
"There is the runway just off to your right side in about a mile", the controller told him.
In an interview with CNN, Jeremy Kaelin, a former co-worker of Russell, recalls him as a "nice guy" and a hard worker.
He also says: "I've got a lot of people that care about me".
"I would like to apologize to each and every one of them", the man added.
All flights were temporarily grounded at Sea-Tac Airport for reports of the security breach Friday night.
Eckrote said it was very fortunate that the plane crashed in a relatively unpopulated island. Based on video from KIRO 7, the crash has started a forest fire on the island.
"It is highly fragmented", she said of the plane.
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