I say we go for someone that people think is innocent. Yams is the cops. Could be protected if the doctor figured it out. Psy is an asshole. He named another mafia and got the town behind it and if the doctor can't figure out who the cop is then psy gets protected.
If we are going to take a risk then we I think we try Yams.
If we don't take a chance then I say we kill someone who has been investigated.