The main problem with dog attacks is always dog owners.
It doesn't matter how big or small the dog is, it has the capacity to attack when the mood takes it.
Unfortunately, dog owners are reluctant to accept this as an inbuilt biological fact about their pet.
The majority honestly believe that their pet is part of the family, and would 'never hurt a fly' - based on the fact that the dog has not attacked anyone yet.
You'd hope that the first time was always the last time, but as so often, the first time has tragic consequences, as here, once again.
Any number of circumstances or unknown and not-understood signals can make a dog attack - it is naive in the extreme to believe that because you love your pet, and he 'loves' you back, that this primal instinct is simply not present in his brain.
It is, and if circumstances align, it will trigger an attack from nowhere.
Dogs are pack animals, and the head of the household is 'top dog' in the dog's mind.
But that does not mean that the dog will not one day spy its chance either to challenge for leadership, or to move up the pack a position or two, and that can mean attacking the head of the household, or a 'lesser' member, including children and babies who are easier targets.
Of course, the majority of dog owners are responsible, and train and care for their pet who loves a happy life with never a hint of aggression.
But the fact remains that any dog anywhere anytime, can attack if it feels the need, and there is nothing anyone can do either to see it coming, or to prevent it.
That is why situations like this will continue to make news, and if the dog is big, strong, and savage enough, such as a banned breed, then serious injury or death is always a very real possibility.
It's no use saying the dog has never 'turned' before, you'd hope that if it had, it would have been humanely destroyed, but as here, it only takes the one time.
It will happen again, because dogs do what dogs do.