Are you KIDDING me? What (or who) the H-E double toothpicks does he think he is? If you even consider his threats, you'll be kicking yourself in days, weeks, and months to come because he will then feel 10 feet tall and bullet proof!!!
You will be doing yourself and the neighborhood a favor by reporting him and then if he does not pay the vet bill, then its time for small claims court. You have the LAW on your side.