The reason I believe that the true killer has something to do with the Sonozaki-family is because of what Mion said in the fifth arc. Remember how she said that her position in the family doesn’t have any power at all, and that she only acts as a spokesperson. Furthermore, she believes that there is someone, other than Mion, who’ll inherit her true position.

Didn’t she talk about Shion, wo in fact is the sibling with that tatoo on her back?

and while it’s true that rika could have just ‘protected’ (with the strength of a 12yr old girl…) irie+tomitake+takano, the reason why she doesn’t is because it would lead to important plot/ending detail being given too quickly~ because she’d realize who’s the culprit, which is minagoroshi/matsuribayashi spoiler

Also, if Mion and Rena didn’t try to cure Keiichi from the disease in the first arc, how does that explain the sixth arc, in which Rena tried to embrace Keiichi?

For the cure, I don’t think that believe that Dr. Irie even knows of the disease, we have been given no indication that he knows anything about it. In the third arc, he just believe that Keiichi was delusional, not that he had a disease. I mean, if Dr. Irie had the cure to the disease why wouldn’t he petition for a mass immunization of the population at the first sign of infection?

I’m thinking just like you are and that is Dr. Irie is murdered because it means that if he is kept alive that he will figure out about what is going to happen to a certain degree, such as the disease being released. This is why he is poisoned, to keep him from interfering after the plans are set into motion.

As for the henchmen, I don’t think that they are Sonozaki related. Remember back when Shion was going through the distinction, having her fingernails ripped out, the henchmen that held her down were just nothing more than mafia-like street thugs, not high trained assassins. I just doubt that the Sonozaki family equips their henchmen with silenced pistols when they are sort of like the yakuza of the town. I think that the real killer(s) is controlling those guys and is using the Sonozaki Family to a certain degree, but is not related to them.

On a final though, last episode we saw that Hanyuu was some sort of spectral spirit or something like that. Now in the third arc, remember that Keiichi heard some footsteps like someone was following him? I think that was Hanyuu. In that arc, Rika knew that Keiichi was the one that was infected and sent Hanyuu to keep tabs on him. I’m gonna go out on a limb here and say that this was how Teppei’s body was dug up and moved by Rika. Although I do see the ridiculousness in this as Rika wouldn’t be able to move, or much less dig up a full grown adult’s body, but is fun to speculate.

Sorry about the wall of text, but I’ve just been think about this stuff for a while and had to write it down and get it out. Thanks once again for blogging this series, I always look forward to your posts and theories for this series.

I need to rewatch the first series, though, as this is one anime where paying careful attention to little details is key. (:

-Tom