A deadly shooting at UAB Highlands appears to be a case of workplace violence, police said Thursday. "During our investigation, we determined that employee relations led to this incident," said Birmingham police Lt. Peter Williston. Investigators say a hospital employee -- 31-year old Trevis Coleman-- killed nursing supervisor Nancy Swift, 63 on Wednesday night. He then shot and injured contract employee Tim Isley, 28, before committing suicide, detectives said. Williston says the motive remains under investigation. "We're still trying to discover the exact relationship that was taking place during the incident." UAB says a "robust assessment" of security is underway.