At least one person is dead and at least three others were injured following an early morning shooting at Northern Arizona University in Flagstaff. The suspected shooter is in custody, and the campus, which has 20,000 students, is no longer on lockdown, school officials said on social media Friday.

The identities of the victims have not yet been released, and the motive for the attack was not immediately known. A press conference regarding the shooting was scheduled for 6 a.m. MST, school officials said.

This is the second shooting at a college campus this month. Chris Harper-Mercer, 26, allegedly gunned down nine people before killing himself at Umpqua Community College in Oregon last week. Nine others were injured in the attack, the New York Times reported. An investigation into a motive for the shooting is ongoing.