Hello c:

You can't.

excon

If you really want to know for a legitimate reason you can call the local Probation and Parole office and ask them. You could look up the person's criminal case docket and see if anything has been entered regarding parole or probation. If your county does not have an online web site you can call the Clerk of Criminal Courts and ask to look up (i.e.) John J. Smith and give the person's approximate age.