Los Angeles County Olive View-UCLA Medical Center in Sylmar was locked down Thursday for about three hours amid reports that a gunman was on site, authorities said.

Deputies were sent to the hospital at 14445 Olive View Drive around 9:20 a.m. after a hospital staffer reported a man with a handgun on the second floor, according to the Los Angeles County Sheriff’s Department. The entire campus was evacuated including employees, patients and visitors.

The facility resumed normal operations after authorities cleared the hospital floor by floor and completed the search of the area, around noon.

The investigation to find the suspect is continuing, and there is no surveillance video available at this time, authorities said.

Anyone with information about the incident is encouraged to contact the Sheriff’s Department.