Evidence suggests 44-year-old Joshua Mjoness was en route to Boise when he was arrested with a 9 mm handgun and 50 rounds of ammunition, authorities say.

CHEYENNE, Wyo. — A North Dakota man arrested in Yellowstone National Park threatened to shoot as many as 20 people at an office in Idaho if his wife didn't identify a man there he suspected of having "emotional affair" with her, according to investigators.

Park rangers arrested Joshua James Mjoness, 44, of Christine, North Dakota, at a picnic area on Sept. 18. He had a 9 mm handgun and 50 rounds of ammunition in his SUV, according to court records.

Evidence suggests Mjoness, a former school board member, was on his way to Boise, Idaho, Mark Trimble, spokesman for the U.S. Attorney for Wyoming, said Wednesday.

Sheriff's officials in eastern North Dakota used Mjoness' cellphone records to track him to the Yellowstone area. Earlier that day, Mjoness texted and called his wife and her brother, saying if she sent a photo of the man he sought, "only two people would die rather than 20," National Park Service Special Agent Jacob Olson said in a sworn statement.

Mjoness allegedly sent her a picture of the pistol with the message, "Up to you."

Court records did not identify the man Mjoness sought or where in Boise he worked.

Mjoness was jailed on federal charges of illegal gun possession and making threats. Bond was to be set at a hearing scheduled Thursday.

Federal public defenders representing Mjoness declined to comment Wednesday.

Mjoness was one of three Richland No. 44 School District board members recalled by voters in 2018 after a scandal involving alleged hazing in a high school locker room in Colfax, North Dakota.

School board President Nathan Berseth, who briefly served with Mjoness, told The Associated Press Wednesday he was surprised to hear about the events leading to his arrest.