PORTLAND, Ore. (KOIN) — An Alaska Airlines plane made an emergency landing at Portland International Airport after a “credible threat to an authorized occupant” on board, and now the suspect, identified by the airlines as an off-duty pilot, is facing 167 charges in connection with the incident.

Officials with the Port of Portland identified the suspect as 44-year-old Joseph D. Emerson, who was taken into custody after Alaska Airlines Flight 2059 operated by Horizon Air was diverted to PDX. Emerson faces 83 counts of first-degree attempted murder, 83 counts of reckless endangerment and one count of endangering an aircraft.

According to Alaska Airlines, Flight 2059 was headed from Everett, Washington to San Francisco on Sunday evening when they reported a credible threat.

The threat came when Alaska Airlines said an off-duty pilot, later identified as Emerson, sitting in the jumpseat caused a disturbance in the cockpit of the plane and “attempted to disrupt the operation of the engines.”

Emerson was certified to fly commercial, as well as transport single and multi-engine planes.

“An experienced pilot is especially dangerous in that cockpit,” said Joseph Schwieterman, a transportation professor at DePaul University. “We saw the pilot, indeed, turn off the engine thrust. That’s really a worst case action that could have lead to terrible things.”

The crew managed to secure the plane without losing engine power and Alaska Airlines said they worked with air traffic control to divert the flight to PDX.

Emerson is currently at the Multnomah County Detention Center.

Neighbors living next to Emerson in Pleasant Hill, Calif. say they are still in shock, describing the pilot and father as normally kind and upbeat.

“We still can’t believe it. We’re still shocked. Doesn’t sound like Joe at all. I don’t know what happened to him mentally that he would do something like that,” said Karen Yee.

According to the Port of Portland, the incident is under investigation by federal and local law enforcement agencies.

“I am grateful for the professional flight crew and air traffic controllers who stepped up to guide this plane safely to Portland. FAA supports law enforcement in their response and will be focused on any safety considerations for the future that emerge from investigations,” said Transportation Secretary Pete Buttigieg in a social media post.

The plane’s passengers were all able to board a later flight.