DICKINSON, N.D. -- The 22-year-old flight attendant accused of fabricating a bomb scare at Dickinson’s Theodore Roosevelt Regional Airport has been charged in federal court.

Justin Cox-Sever, 22, of Tempe, Ariz., is charged in the U.S. District Court for North Dakota with two felony counts related to interfering with the navigation of an aircraft and communicating false information which endangered the safety of an aircraft.

Cox-Sever previously was charged in Southwest District Court with felony terrorizing, though that charge was dismissed Monday, the same day the federal case was filed.

In an affidavit, FBI Special Agent Daniel Genck wrote that on Sept. 9, he learned that SkyWest/Delta Flight 4770, bound from Minneapolis to Dickinson, was making an emergency landing "due to the presence of a suspicious bag on board that was 'beeping.'"

The Stark County Sheriff's Department, Bismarck Police Department Bomb Squad, FBI and other agencies responded to the airport, which was locked down until the aircraft could be cleared of potential explosives.

The suspicious package turned out to be a white plastic bag with rolled up towels inside. There were no electronic devices or explosive materials in the bag.

The aircraft's captain, first officer and flight attendant — Cox-Sever — all told the FBI that Cox-Sever found the bag in the rear of the plane and notified the flight deck. Through the speaker system, the crew asked if the bag belonged to anyone. Nobody claimed it.

"Cox-Sever then noticed the bag was beeping and notified the flight deck," Genck wrote.

No other passengers reported hearing a beeping.

The captain responded by declaring an emergency and landing the aircraft.

Cox-Sever also allegedly told Genck in an interview that he had a similar encounter on a July 7 flight, American Airlines 2928 from Charlottesville, Va., to Chicago. He said on that flight he discovered a written threat on the wall of the lavatory stating there was a bomb on the plane. That flight was diverted to Charlottesville and no explosives were found.

Under further questioning, Cox-Sever confessed to planting the suspicious bag, saying he acquired it from a food delivery a few days prior and the towels were his own, Genck wrote. He also allegedly confessed to fabricating the other incident on the July 7 flight to Chicago.

"Cox-Sever stated he was extorted by a friend who told him that he needed to 'bring down' a plane or else they would harm him and his family," Genck wrote.

He later "recanted his claim of extortion and admitted he had written the threat willingly," according to the affidavit.

Magistrate Judge Charles Miller Jr. ordered Cox-Sever released under federal supervision. Cox-Sever had been in custody — at Burleigh County Detention Center, and before that the Southwest Multi-County Correction Center in Dickinson — since Sept. 9.

One of the conditions of Cox-Sever's release is that he is barred from flying without prior approval.

"The practical reality is he may have to go Greyhound until this gets resolved," Miller said.

The FBI in Virginia is continuing to investigate the bomb threat on the Charlottesville flight.

SkyWest Airlines, which operated the North Dakota flight for Delta and the Virginia flight for American Airlines, initially placed Cox-Sever on administrative leave. SkyWest spokeswoman Marissa Snow on Tuesday said Cox-Sever is no longer employed by the airline.

"The safety and security of our customers and people are our top priority," she said.

Cox-Sever could receive up to 40 years in prison if convicted on both counts in North Dakota.