I think Sadia could be right about the poisoner being the one who killed David. The first night did give a lot of description of characters after all, so unless Pendio changed up his style, or that's the way the mafia is able to kill, both of which are doubtful. Plus, that makes more sense to me than the mafia killing a vanilla townie. As I said before, he had a lot of suspicions on him, so it would've been beneficial to them if he was alive to take some heat of themselves.
If the poisoner is the cause of David's death, I think either the jailor successfully roleblocked the correct mafia member, or the mafia is choosing not to be active at night to throw us off. If the jailor was successful, I'm wondering if the target was the same person both nights, or if they jailed two different people and somehow the vig had also chosen the same. The night scene seems to imply that it was the same person two nights in a row, but it could also simply mean that the vig failed to find their target, even if it was someone different, a second night.
Anyway, I don't have any clue who to be looking at right now. I'll reread through the thread when I have some extra time tomorrow after work.