You can trace a person by following him home from work, right? That is what a private investigator would do.
You can sue a person for owed rent. You must be able to serve a summons and complaint upon him, though, so you have to figure out where the living address is.
sure you can sue them and serve them with the summons at their job. I would suggest writing a letter first and make sure they don't have any counterclaim possibilities against you. See an experienced attorney to make sure you won't have exposure to any counterclaims.
If they did not give you notice of problems with the rental unit by this time, their remedies under the Chicago Residential Landlord & Tenant Ordinance may have long since expired, so if they do make any counterclaims, they may not have exercised their rights properly. As to rent, did you notify them of any damages? That you were withholding their security deposit? These things also need to be verified because of the Ordinance (along with any interest). Finally yes to confirm you can serve them with a lawsuit anywhere you can find them.
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