Mechanic bought my car with blown plug then stole car can't find

[tullphd]

Hello,
I had a 2005 Ford Escape it required engine work. It blew a spark plug out, needed head, ect. Looked for a mechanic on craigslist to fix engine, found engine rebuild advertisement. He had car towed to his home which was near his shop. We met up and he stated that he would like to just buy the car. We agreed upon a price. and made contract.He has made about $600.00 toward the $3,900.00 price and has now become unreachable. He has moved closed his shop, communication up until May was sporadic but he did make the above payments. Now without a way to find him he is in or was in Columbia Tennessee and I am now on Oklahoma. I changed my insurance on the car when it was not drivable to a in repair not driving policy, and I am still making my payments on the car — for the loan and the storage/under repair insurance.
His phone is disconnected, the shop is out of business, he has moved ?? somewhere, and I can't find him anywhere.
The Craigslist ads for this mechanic are not available anymore, and unfortunately I do not have a copy of the original listing or an email address, only a bogus address that I used to send him the contract to which we then completed in person, so I presume that the email address was bogus. Have tried to email and call the sender (his Aunt) for the details that he provided when the last past payment was sent to Wal-Mart.

What is the course of action I should pursue?

Out of state and desperate.