Lol, when Lisbon said: "..or at least give us a PLAUSIBLE motive" my first thought was this website.:D We need to get a life.:)

I'm still accusing the sheriff but I really don't know anymore..

There was something in that moment when he reached out to help Patrick on the roof and they showed their hands together..It was very mysterious. Like the murderer who killed his family, is reaching out to him, to help him and in a way, play with him..
I only got that feeling from the sheriff so far..:)