A University of North Carolina faculty member was shot and killed in a campus building, officials said Monday.

A suspect was arrested about an hour and a half after shots were reported, UNC Police Chief Brian James said at a news conference. Students and faculty at the flagship campus had barricaded themselves in dorm rooms, offices and classrooms for hours until a lockdown was lifted.

“This loss is devastating and the shooting damages the trust and safety that we so often take for granted in our campus community,” UNC-Chapel Hill Chancellor Kevin Guskiewicz said. He apologized to students who are “feeling uncertain about your safety right now.”

Authorities are not releasing the suspect’s name and formal charges have not yet been filed, James said. It’s unclear if the suspect knew the victim, who police have not yet named while they reach out to relatives, James said.

The shooting was in Caudill Laboratories, which is closed while evidence is processed, James said. He said a motive isn’t known and the weapon has not been found.

Emergency sirens sounded about two minutes after a 911 call came in reporting shots fired, James said.

There were no other deaths or injuries, James said.

About three hours after warning students to seek shelter indoors and avoid windows, the school posted on X, formerly known as Twitter, “All clear. All clear. Resume normal activities.”

The school’s first alert was sent out just after 1 p.m. At 1:50 p.m., officials posted on X that the shelter-in-place order remained in effect and that it was “an ongoing situation.” About 40 minutes later, the school added a post saying: “Remain sheltered in place. This is an ongoing situation. Suspect at large.”