My dog was viciously attacked by a dog. Now, the same dog has attacked another dog and killed it. What actions can be taken?

Three years ago while walking on the street a dog tore out of a doorway and attacked my dog, injuring her seriously. I made a police complaint but was told that Florida/Lee County Law did not provide for any restrictions on the dog. Now, while its owner was walking the dog it got away from him and raced to a driveway where a woman and her two dogs were standing. The dog grabbed one of the dogs and shook it to death. The owner is in his 90s and walks the dog while riding a recumbent bike. He could not even get out of the bike to help the woman. He is clearly unable to control a vicious dog and we live in an area where almost everyone has a dog. My dog still is afraid of other dogs and I have PTSD from the incident. He payed my dog bills but that is not enough. The dog needs to be relocated or destroyed. What can the police do? What can I do?