Years ago a guy working for me went to a Gun Show. While there he bought a pistol. Monday morning he came to me and said he thought he might have bought a stolen pistol. Judged by how the transaction was handled. I said you have two choices.
1. Go to the County Sheriff with the pistol and let him run it. If it's stolen he will confiscate it and it'll likely never make it back to the original owner but rather sit in an evidence cage for several years.
2. Keep the pistol and move on.
He chose #1. Went exactly as I suggested it would in regards to confiscation.