Mishnayot! If an ox goes to do one thing, including intending to kill another who is not the one who was killed, the ox is "exempt." Plus, when subsequent damage (or death) to something the ox is accustomed to doing... It's not really considered the ox's intent to damage/kill. Also, the verse that establishes how a person is held accountable for premeditation. Plus, a mishnah on the different categories of owners of a killing ox, and which owners (according to whom) are still fully liable.