Investigators have identified a former student as the man suspected of calling in a bomb threat that shut down Colorado Mountain College’s campus in Leadville on Monday.

Adam Slattery, 32, was taken into custody on the campus. Authorities say he is not cooperating with investigators.

“He wasn’t happy with his grades,” Lake County Sheriff Rodney Fenske said at a morning news conference.

Slattery, of Leadville, is being held on suspicion of false reporting of explosives, resisting arrest, menacing, criminal extortion and harassment. He is due before a judge on Tuesday afternoon.

Colorado Mountain College says Slattery was enrolled for the fall 2016 semester and that he was taking a mix of online and in-person courses. He was not a student at the time the threat was made.

Fenske says Slattery apparently called in the threat to Colorado Mountain College’s campus in Glenwood Springs on Monday, which in turn notified the Garfield County Sheriff’s Office. The sheriff’s office determined the threat was intended for the college’s Leadville campus, alerting authorities there at about 9:30 a.m.

According to an arrest affidavit for Slattery, in one of the calls he left a voicemail and said: “This is Adam Slattery. I don’t have my student number handy. … I feel that she religiously discriminated against me in her class last semester and failed me wrongfully. I am really (expletive) furious.”

In another message, the affidavit said, Slattery said an explosive device had been planted near the library. “If the demands are not met by the end of the semester, the device will be detonated in a spectacularly safe manner. (laughs) Is that a (expletive) bomb threat?! I don’t think so.”

The calls shut down the Leadville campus for most of Monday until a bomb squad from El Paso County arrived and cleared the scene. Investigators were honing in on a backpack as an item of suspicion.

Officials said the campus — including the backpack — was “found free of any threats.”

Students and staff were evacuated to the school’s cafeteria during the campus search.

The affidavit says officers arrested Slattery outside of the campus’ library on Tuesday morning, but not before there was a struggle as they attempted to handcuff him.