Fifty-four-year-old Ronald Rice, who was already in prison for the sexual assault of another child, attacked Edwin Gulbransen more than 30 years ago as the boy was riding his bike to a convenience store in Oak Forest.
Originally, Rice told police he struck the boy with his car and then panicked when the boy wasn't breathing, and dumped the child in the woods.
But investigators now say Rice intentionally hit the child.
Rice also admitted to prison employees that he sexually assaulted and murdered Gulbransen.
