IIRC, it was the night before the trial when Ivan wakes up and the devil goes on that monologue. Just before Alyosha knocks on the door and tells him that Smerd

IIRC, it was the night before the trial when Ivan wakes up and the devil goes on that monologue. Just before Alyosha knocks on the door and tells him that Smerdyakov hanged himself.