It's pretty simple actually. The whole thing is based around Joe. It's Joe's story that they're all "writing" chapters for. None of the other murders related to the cult had anything to do with the people's own problems. Those problems are what drew them to Joe in the first place. It was related back to that because…

he defends ava to augustine, and augustine is basically, "good one, nice joke on defending her, or you're not kidding?" and then he flat out tells ava that johnny went to duffy and is in his pocket.

Um, actually, three is a trend. Two is a coincidence.