Whether or not 911 calls are made available to the public depends on the state law in the state in which you live.  In New York, for example, they are available for a short period of time before they are destroyed.  Some states have always banned them from the public - Missouri, Pennsylvania, Wyoming and  Rhode Island - and some states are considering legislation to do so: Alabama, Ohio and Wisconsin.  The best thing for you to do is to ask a criminal atttorney licensed in Illinois.  Additionally, sometimes the taps may not be public record but a transcript of the tape may be under FOI act.  Good luck to you.