Odometer Fraud

I bought a used truck for $6,800, the miles have been rolled back from 330,000 to 105,000 and then sold to me. I did a Carfax and the guy I bought it from had the title mileage exempted when he bought it. When I found out about the mileage and I called the police. The police said there's nothing they can do because I can't prove that he rolled back the miles. This guy sold four trucks in the last month all with the same exact mileage. He also deletes all of his listings immediately after he sells them so he doesn't have a vehicle history. He also claims he's not a dealer but it looks like he sells about four cars every month. The police have not been helpful and tell me there's basically nothing they can do I should call an attorney. I reached out to the guy I bought it from and he's refusing to take the car back. Another thing I noticed about this seller is that he was selling used cars in Florida and then moved to Pennsylvania. This truck is basically worthless with that many miles so I'm not sure what to do, hiring an attorney is not cheap. Any advice?