No mentioning of the old lady trying to attack the dog,she wanted the dog
to stop biting.
Highly reactional dog,this happens not only in Pitbulls.
The fact that the dog already bit before and no action was taken means you could wait for it to happen again.
Aggression in dogs or in humans need to be controlled or it will happen
again.
But,they still loved the dog,mai pen rai.
Like other posters have said,end his life now before he goes off again.
Probably put in a small kennel until they feel sorry for it and then ,it will happen again.