The owners should be held responsible for all costs, including the costs of sending the cops, animal control, your medical costs, keeping the animal in a shelter, etc. Assuming, that is, they can be found.

There are actually some people, drug dealers mostly, who teach a dog to attack the face or the gonads. They also have the animal operated upon so that it cannot bark or growl, so there is no warning when it attacks. THESE people should be euthanized when the animals are.

But those are just my own opinions. YMMV.