If the dog is leaving your property to attack, goodbye puppy. People walking by your house is a rationalization for the behavior. The dog has an issue and it's a 3 time loser in this account. Sucks, but, reality is it's going to do it again. It's a bomb waiting to go off. What if it attacked an infant or small child and went to town, because the kid walked by your home... with multiple attacks on record, you are looking at potential prosecution.
Additionally, why is the dog able to leave you property? Hate to say it, that is on you being negligent in maintaining control of your dog. Harsh reality from a legal perspective.
Sucks because we had to get rid of a dog one time that was kind as could be, unless you came to the house. Then all hell broke loose. She bit another dog and that was that... Dog gone!
