I found a newspaper article. It happened in Quincy (been their often, I have ex-in-laws there :-). If you send an email to firstname.lastname@example.org
I will send to you.
I will continue looking thru my resources. I have tons so will take a day or two to get thru them all.
As to other things you can do:
1- contact the local historical society and ask them to
search. 90% I find are kept by them.
2- if no luck check state historical society and state archives.
3- check for courthouse records
4- check local newspaper's (in service at that time) archives
5- check the local libraries. Usually a historical or genealogy librarian will search for you.
6- send an email to email@example.com
with the inmates name and time they were at Pontiac/Joliet and they will respond back with a one page sheet for each prison term whch shows name, prisoner number, institution, county, crime, term, date sentenced, date received, paroled and discharge date. At least they did when I used them a couple yrs ago. That will eliminate the need to have a lookup done at the State Archives.
I am off to continue the search :-)