Two people hug after a shooting at the John W. Harshbarger Building on the University of Arizona campus in Tucson, Arizona, on Wednesday.
CNN  — 

A professor was shot and killed Wednesday on the University of Arizona campus in Tucson, authorities said, and a suspect has been arrested.

University police first received a call around 2 p.m. local time reporting that a 46-year-old former student had entered the John W. Harshbarger Building, University of Arizona Police Department Chief Paula Balafas said during a news conference.

“The student wasn’t allowed to be in that building,” Balafas said. “The caller wanted the man escorted out of the building by police.”

As authorities were en route, they then learned that someone had been shot inside the building, Balafas said. Police also learned the suspect had fled the scene.

At around 5 p.m., the suspect was taken into custody by the Arizona Department of Public Safety following a traffic stop near Gila Bend, about 120 miles west of the university, Balafas said.

The shooting victim, who has not been named, was taken to a hospital where they were pronounced dead.

The weapon used in the shooting was a handgun, Balafas said, adding that the shooting is under investigation.

Balafas could not confirm the extent of relationship between the former student and the professor. The chief also could not confirm how many shots were fired.

“It’s a tremendously tragic event,” Balafas said. “We feel so incredibly bad for the professor’s family, friends and colleagues, and our hearts just really go out to them.”

CNN’s Aya Elamroussi contributed to this report.