Just finished the book. Absolutely loved it. The characters and the philosophical/religious musings. The plot was excellent with all the pieces of the puzzle fitting in. Though I have to admit, there's one loose end in the book, which I can't make sense of, and it's bothering me! That missing piece is the reason behind Katerina Ivanovna's two visits to Smerdyakov. Was any light shed on the reason behind this? Maybe I missed that. The last reference to this story in the book, as I recall, is the devil tormenting Ivan about having forgotten to ask Smerdyakov about Katerina's visits. Did I miss something here? The reason I'm curious about that reference is that when I read it, I imagined that perhaps Katerina had somehow colluded with Smerdyakov to kill Fyodor, in an attempt to frame Mitya... I'd love to hear someone's insights into that...