ROLLA, Mo. (AP) A student arrested Tuesday after threatening “terrorist-type” actions at the University of Missouri-Rolla was depressed and anxious over his school work, Rolla officials said.

The suspect, a graduate student at the school, was arrested and the school’s civil engineering building was evacuated after he was found with a white, powdery substance and “possible bomb materials,” school officials said. Acting Rolla Police Chief Mark Kearse said when police arrived the student was holding a knife, held up a bag and said: “This is a bomb.” He also claimed to have anthrax.

Police used a stun gun to subdue the student. Officials declined to release the student’s name or any identifying details. Police also found a note with the student threatening to destroy the building, Kearse said. Rolla Mayor William Jenks and Kearse said the student had been distraught over his grades, which may have led to the incident.

Officials at UMR reacted in the same way their counterparts at Missouri Southern would, if faced with the same situation.

“We’re not a law enforcement agency, so we would hand it off to the Joplin Police Department,” said Ken Kennedy, director of public safety. “We would be helping them in any way we could.”

Kennedy said Southern has not faced such a serious situation, but the University is not immune.

“About four years ago, we had a threat,” he said. “But it wasn’t specific enough to merit evacuation.”

The UMR Butler-Carlton Civil Engineering Building was evacuated and 23 people who were inside the building when the suspect was arrested were being decontaminated in tents set up on campus.

The campus in south-central Missouri was shut down during the episode as police surrounded the building about 2:30 a.m.

Jenks said only the civil engineering building was involved.

“We have no hard evidence that there’s anything wrong in the building but we simply can’t take a chance,” Jenks said. “We’re taking a very cautious approach.”

Classes were canceled until at least 10 a.m. while officers investigated. A nearby Catholic school also canceled classes.

The Fort Leonard Wood Explosive Operations Division was investigating the possibility that a bomb may be in the building.