The man will have already reported the theft to the police, and will have identified the actual thief. If there is reason to believe that the initial police report was false, and that the man stole the four-wheeler himself, then the police may investigate the man to determine whether he was involved in the theft.

The owner may be able to make a negligence claim against the borrower for failing to safeguard the four-wheeler -- if the owner attempts to do so and the borrower has homeowner's insurance, he should turn the claim over to his insurance.