What we know about the off-duty Alaska Airlines pilot accused of trying to shut off a plane's engines mid-flight

The off-duty pilot accused of trying to shut down the engines of an Alaska Airlines plane midflight on Sunday said he was having a nervous breakdown and told the flight crew he needed to be subdued, according to a federal complaint.

Alaska Airlines pilot Joseph D. Emerson, 44, has been charged in federal court with interfering with a flight crew, the US Attorney's Office for the District of Oregon announced Tuesday. That charge comes on the heels of dozens of state charges in Oregon, including 83 felony counts of attempted murder, 83 counts of reckless endangerment and one count of endangering an aircraft, booking records show.

Emerson attempted to cut fuel to the plane's engines while the flight was en route from Washington state to San Francisco on Sunday, according to authorities. But it was the quick action of the aircraft's captain and first officer that kept the engines from failing completely, the airline said.

Emerson was subdued by members of the flight crew but then attempted to grab the handle of an emergency exit during the flight's descent, according to a release from the US attorney's office.

The flight was forced to divert to Portland, Oregon, where the suspect was taken into custody by Port of Portland police, the agency said in a statement.

While in custody, Emerson told a police officer he became depressed about six months ago, according to an affidavit authored by an FBI agent and included alongside the federal complaint. Emerson denied taking any medications, the affidavit says, but he did discuss psychedelic mushrooms with the responding officer.

"The officer and Emerson talked about the use of psychedelic mushrooms and Emerson said it was his first-time taking mushrooms," the affidavit says.