A woman was shot and killed inside a parking garage in the complex. UIC police say they arrested Earl Roberts a half-mile away at 14th and Damen. There was a foot chase around 6:30 a.m., and a UIC officer caught up with and arrested Roberts. Officials say a gun was recovered.
Police say Roberts is a housekeeping employee of the hospital and had keys to sensitive areas.
The UIC Medical Center was under a lockdown for much of the night early Friday as police hunted for the gunman after the shooting on West Taylor Street.
Police say the gunman shot and killed the woman, believed to be his ex-girlfriend or ex-wife, on the second floor of the garage. Police couldn't be certain whether the gunman fled the area or ran into the hospital complex.
"There was initially a belief that the individual entered the hospital. However, we have now conducted two searches of the hospital and every room very thoroughly. There has been no sign that the individual at any point was in the hospital," said Mark Rosati, UIC, associate chancellor for public affairs.
Around 5 a.m., the university said the hospital resumed normal operations.
Rosati said the suspect had worked at the hospital for 15 years.
The garage is near the hospital but not attached to it, Rosati said. He wasn't sure whether the hospital has metal detectors but said the university has security cameras posted indoors and outdoors across its 250-acre campus.
The Associated Press contributed to this report.