FLAGSTAFF, Arizona: An overnight confrontation between two groups of students escalated into gunfire Friday when a freshman at Northern Arizona University killed one person and wounded three others, authorities said.

University police chief Gregory T. Fowler identified the shooter as 18-year-old Steven Jones and said he used a handgun in the shootings at about 1:20 a.m. Friday. Police were still interviewing Jones and he had not been booked into jail Friday morning.

The university in a statement identified the student who died as Colin Brough. The victims being treated at Flagstaff Medical Center are Nicholas Prato, Kyle Zientek and Nicholas Piring.

“This is not going to be a normal day at NAU,” said school President Rita Cheng. “Our hearts are heavy.”

She called it an isolated and unprecedented incident and said classes would go on as scheduled Friday.

The parking lot where the shooting happened is just outside Mountain View Hall dormitory on the Flagstaff campus, which provides housing for many of the campus’ sororities and fraternities.

Iowa City, Iowa-based Delta Chi Fraternity said Delta Chi members were involved, but Executive Director Justin Sherman said in the statement that the organization doesn’t have detailed information about the identity of the victims.