1. Large and/or aggressive breed of dog? Yes. Pit Bulls - bred to fight and ignore submission and keep fighting.
2. Running loose, often >1 running loose? Easily leaped over fence = running loose. Two of them packed up and ready to kill.
3. Prior aggressive behavior by dogs? Yes, they had attacked this guy before, and several other people as well.
4. Unrealistic expectation of gentleness from dogs by owner, often despite #3 above? Yes. She thought it perfectly OK for them to be in a yard they could (and had before) escape at will and to attack people (as they had before).
And is she being held criminally libel for it or will the mob merely satisfy themselves with the death of the dogs?