You might be able to sue the individual who transferred the title. Depending on the value of the car and the judgment limits in your state, you might try small claims court. That way you would not need to hire an attorney.
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Most police departments won't touch a case like this for a number of reasons; however, the Illinois Secretary of State Police might as they deal with fraudulent vehicle transfers. If you haven't reported it to them I would suggest you do that immediately. If you can find the person who fraudulently transferred the ownership you could sue that person; however, you're probably going to need an attorney to do that and the cost in terms of attorney's fees and court costs might be prohibitive for you by comparison to the car's value. You may also be able to go after the current owner for what's called "unjust enrichment".