I agree with Logan about the microchipping. It is the best way to prove the dogs ownership.

A thought.... can you get copies of the newspaper ads you ran trying to find the rightful owner and then the vet bills (hopefully some 30 days apart) to take to a lawyer. Some lawyers work on a free basis and get paid after they win the case. They will be able to tell you for sure if you have a paw to stand on in getting Tobey back.