First you must determine if the check you sent to him was cashed by him. If in fact it was received by him and cashed, then you would have to the pursue him in his own state and possibly even his own county. Depending on the circumstances, you might be able to prosecute him for fraud, mail fraud, or larceny after trust, among other things. Local jurisdictions are usually more helpful when the accused has a history of being on the other side of the law. It's a long trip and may not be worth the effort on your part. I wish there was a way for this web site and it's members to help. Good luck!