yooo I'm fucking cracked I can't believe I actually deduced the correct culprit after re-reading the series all of these years. Author was right he did atleast for the most part actually set out all of the threads for the mystery to be solved. I'm pretty content lmao.
I was so close to the real culprit all those years. But I have a question for fellow readers, where the hell did Azuma come from? And why in the end it's kind of implied that Hibiki is treating Asuma as her brother and not Shizuka ?