It depends on the temperament of the dog and how it is raised. My son and I both got pits at the same time. His is more aggressive than mine. Mine is more likely to beat you to death with her tail from wagging it so hard.
I am really scared of the pitt bulls. I have never seen one that does not look like it wants to bite me. My thought is this. The pitts may be silent attackers true, but if it was a stranger that opened that door wouldn't said stranger have a huge hunk of flesh out of his arm or leg? If anyone owns a pitt I would love to hear what they think the chances are that pitt bull bit the killers if they are strangers. ( I know this sounds a bit sarcastic but I don't mean it to be. I would genuinely like to know your thoughts in relation to your own dog on the chances the pitt bit a stranger.) Another thing. If the dog bit the killers can they get DNA from the dogs mouth/teeth?