One victim died, while the second is said to be in stable condition, according to Williston.
There is no additional threat to the public, police said.
Two employees were shot, one fatally, when a gunman opened fire inside the University of Alabama at Birmingham (UAB) Hospital-Highlands on Wednesday. Both victims are in critical condition.
Birmingham police have identified the suspect as a 32-year-old black male.
"We do know it was an employee relations issues that led to what happened", he said.
UAB Senior Vice President Anthony Patterson says metal detectors were in use at the time of the shooting.
All surgeries scheduled for Thursday have been canceled, according to the hospital.
- Authorities say a disgruntled employee killed a nursing supervisor and wounded another medical worker before killing himself inside a hospital in Birmingham, Alabama.
Authorities were unsure of the shooter's relationship to the victims and whether the victims worked at the hospital, Capt. H.R. Watson of Birmingham Fire and Rescue told news reporters Wednesday night.
Police responded to an active shooter situation just before 7 p.m. March 14 and said they found two men with gunshot wounds and another man who shot and killed himself.
Police vehicles are shown outside UAB Highlands hospital following a shooting on Wednesday, March 14, 2018, in Birmingham, Ala.