Towson University officials said all was clear at a campus library Monday night after a report of a possible armed person there was determined to be unfounded.
University police received a call at 6:15 p.m. from a person who said they were inside Cook Library and armed with an explosive device and a handgun, said Ray Feldmann, a university spokesman.
Police evacuated the library and an adjacent media center and searched the buildings floor by floor, but found nothing, Feldmann said.
"We believe it to be an unsubstantiated threat," he said. "We're just very grateful that it turned out to be nothing."
The library and media center reopened at 7:46 p.m.
Earlier, they had put the campus on guard for a possible armed person, though university police officials said there was not an active shooter on campus.
"Police are investigating a possible armed person in Cook Library. Avoid area," they said on Twitter.