Authorities arrested a North Dakota man for threatening to shoot up to 20 people at his wife's office, according to a complaint filed Monday.

Joshua James Mjoness, 44, allegedly demanded his wife send information on a man she had an emotional affair with, investigators said, or 20 people would die in a Boise, Idaho office.

Yellowstone National Park rangers found a handgun and 50 rounds of ammunition in Mjoness's vehicle when they arrested him on Sept. 18. The handgun matched a photo Mjoness texted his wife after making the threat, wrote National Park Service Special Agent Jacob Olson in a sworn statement.

Mjoness also asked his wife's brother for her location, the complaint said. He allegedly said "this is the easiest way out" on the phone.

"Tell your sister to send me a picture of [the paramour] and his information," the brother reported Mjoness saying. "Either two people die or twenty die."

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While taking Mjoness into custody, rangers said he smelled of alcohol. They found empty whiskey and beer containers, plus marijuana.

Officials charged him with illegally using a controlled substance while possessing a gun, making threats and transporting a firearm across state lines to commit a felony.

The case is ongoing, said Mark Trimble, a spokesman for the U.S. Attorney for Wyoming.

Mjoness, a resident of Christine, North Dakota, formerly served as a board member for Richland No. 44 School District. Voters recalled him in 2018 after a scandal of alleged hazing in a high school locker room.

School board President Nathan Berseth said he found Mjoness's threat surprising.

“He was a very passionate school board member and concerned about the district and of course about his kids,” Berseth said. “He was very engaged in the board.”

Mjoness could face up to 25 years in prison, according to the complaint.

Contributing: The Associated Press