Jerell Thomas was indicted on charges of first-degree murder, attempted murder of a peace officer, possession of a stolen firearm and unlawful use of a weapon by a felon.
He remains in custody and will be formally arraigned on Jan. 3 in Maywood.
Detective Allan Reddins, 40, was shot and killed last month, when confronting a man who had allegedly left a bank nearby with a gun.
Thomas was allegedly seen leaving the bank with a gun before he was approached by Reddins and other officers. When officers asked the suspect to show his hands, he allegedly brandished a gun. Investigators say that's when Thomas opened fired on Reddins, leaving him with critical injuries. Reddins died at the hospital hours later.
Thomas was shot in the leg in the incident
Authorities recovered the gun they say Thomas used in the attack. Investigators say he took it from his sister who legally owned the 40-caliber weapon days before the attack after a altercation with his father. Thomas' relative did report the gun stolen.
Police said the attack was captured by both security cameras in the area, the officers' body-worn cameras, and a neighborhood resident who took pictures of the violence.
Authorities say Thomas is a habitual criminal with a previous history of multiple arrests for aggravated battery to a police officer, domestic battery and battery and resisting arrest police officer.
Reddins, a five-year veteran, was the first Oak Park officer to lose his life in the line-of-duty in 86 years.
He was laid to rest earlier this month.