but "pig" was written on jeffrey macdonald's wall. strikes me is it possible to conceive this man would stab himself in order to frame the manson gang by writing "pig" on the wall. none of it made any sense to me. hmm. a pig is a really good example, just the kind of thing i was talking about. you see the word "pig" written in blood. well, that could be evidence that there's manson style crazy hippies who killed the family, or it could be proof that macdonald wrote "pig" to make it seemed he staged the writing to make the police think that there had been a manson-style intruders. evidence is very, very finnicky kind of thing, and how you reason your way with evidence through to some kind of conclusion really deeply fascinates me. >> we have a criminal system where you start with motive, means, and opportunity. where anyone living in a family has the opportunity and the means. just anyone, whether it's sam shepard or anyone -- >> anybody in the family usually has a motive. >> they attribute 0 -- motive to him. one motive is you have an