I have had many pitbulls and made sure he was always under my control! Period NO EXCUSE! As a former owner of 3 pits, I don't think I would sleep again if they hurt someone.
How would you feel if a child was hurt/killed by that dog? Not.that it would be your fault but I would feel horrible knowing I could of prevented it.
Sounds to me like someone ruined the dog. That's on he owners. That being said I'd of shot the thing right then. If this dog is full grown and doing things like that it will probably not be able to be taught to not do so. At least not form it's present owners. I'm a big fan of pit and pit mixed dogs but they have to be trained properly. They are a lot of animal and hard to stop once moving. If allowed to be aggressive by their own or at the whim of their owner it's very hard to get them to stop. And no dog should have to be chained all the time. It might have been what drove it nuts to begin with.
That animal come out of it's yard and into another to attack. That's a HUGE bunch of wrong. It was rather taught behavior or acquired form a lack of time spent with the dog.
The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants. Thomas Jefferson