The suspect, Develt Bradford, 52, was being held at Area 2. He was charged Wednesday night in connection with the deadly robbery at an ALDI store last week. He was charged with three counts of robbery with a firearm and one count of murder.
Police say Bradford and another man, still at large, robbed an ALDI store at 90th and Halsted last week, but during the robbery, police say Bradford shot and killed a security guard, 54-year-old Reginald Lanier. A 67-year-old woman, a customer, was wounded.
A source said Bradford hung himself with pajama-style pants worn under his regular clothes.
He was found in a cell at the Calumet Area headquarters, 727 E. 111th St., and was pronounced dead at the scene at 2:03 a.m., according to the Cook County Medical Examiner's office.
Last week, police released images of both suspects from surveillance video at the store. The suspect on the run is said to be in his 20s or 30s.
The Sun-Times Media Wire contributed to this report.