Officer Michael Bailey was killed outside his South Side home in July of 2010.
Police say Antwon Carter shot and tried to rob Bailey, who was just weeks from retiring.
Carter was charged while he was in jail in an unrelated carjacking case. Prosecutors say he told a fellow jail inmate that he was involved in the murder of a police officer.
Investigators say Carter told them he intended to rob Bailey, but the officer pulled out a gun and the two exchanged fire.
