Three people were killed after a shooter opened fire on Wednesday in a building at the University of Nevada, Las Vegas, sending students running through plazas in the latest scene of gun violence in America.

The assailant died in a shootout with the police, authorities said. A fourth person who was shot was in stable condition at a hospital.

Sheriff Kevin McMahill of the Las Vegas Metropolitan Police Department said the police knew the shooter’s identity but would not release it until later. He did not provide any information about a motive. The shooter was roughly 60 years old, according to a law enforcement official.

The gunfire erupted before noon inside the Frank and Estella Beam Hall rattling professors, students and staff members across campus.