i too have to say its the deed not the breed, staffies are really gentle by nature, a child is more likely to get bitten by the family labrador because of the assumption its a soft gentle lump, animal to animal agression is NOT the same as animal to human agression, i myself witnessed a greyhound chase and kill a cat not that long ago, yet when caught it was very affectionate towards people i still love the breed and would have one if i didnt have chinchillas, this particular staffie obviously has a high prey drive and has been taught to chase by its fluffyfeet for a owner, probably for lamping
it could even be (as no one actually knows for sure) a pitt that has been taught to fight and has escaped from its pen.........yes it still goes on and no not many people can tell the difference between a pitt a staff and a american bulldog,