CNN  — 

A suspect is in custody after a shooting at the University of North Carolina at Chapel Hill on Monday afternoon left a faculty member dead and prompted students and others to shelter in place for hours as police looked for the gunman, school officials said.

Shots were reported fired at 1:02 p.m. ET at the school’s Caudill Laboratories, and a suspect was taken into custody shortly after 2:30 p.m., Chancellor Kevin Guskiewicz said at a Monday evening news conference.

The names of the faculty member and the suspect were not immediately released. It was too early to know a motive for the shooting, UNC Police Chief Brian James said.

“We really want to know the ‘why’ in this case and what led to it,” James said.

The gun used in the shooting has not been found, the chief added.

James said it was unclear whether the victim and the assailant knew each other.

“That will hopefully be uncovered through interviews of the suspect as well as any witnesses that may be available,” James said.

The killing is “devastating and the shooting damages the trust and safety that we so often take for granted in our campus community. We will work to rebuild that sense of trust and safety within our community,” Guskiewicz said.

The school had issued an alert to students telling them to shelter in place at about 1 p.m., later adding a suspect was at large. The university then issued an “all clear” shortly before 4:15 p.m.

Classes and campus activities were canceled Monday and Tuesday, officials said.

During the alert period, university police advised students to go inside immediately, close windows and doors and to wait until further notice, according to an email. A witness on campus told CNN they were locked down in their building and saw armed officers searching campus.

Video from CNN affiliate WRAL in Chapel Hill showed a large number of police vehicles at the campus with their emergency lights flashing. At times, people walked out of nearby buildings in a single-file line with their arms in the air.

A WRAL reporter also recorded video of campus police surrounding a person in handcuffs who appeared to be dressed in a dark shirt and jeans and wearing glasses at the time the school was under lockdown.

This is the second week of the fall semester at the school. The university has a student body population of about 32,000, along with more than 4,000 faculty and 9,000 staff members.

CNN’s Devon M. Sayers and Eric Levenson contributed to this report.