Looking at the hit pattern, I'm inclined to believe Lucario might be the killer. He went after an obvious townie big player on the first day, and then just took the low-hanging fruit that was ThePerm despite it being pretty clear he'd be protected since he was the only relevant hit target. I'm assuming since his description in the role thread says he's still the AA-battery powered car, he didn't even have to use his protection and the doctor jumped in.
Anyway, that's the type of gameplay I've come to expect from Lucario. Even though it seems there's a landslide, I'll vote Lucario.