Regarding the book page 118. As has been noted here, considering his field of study it would be normal for him to have books on crime, criminology, etc, so for them to single this out must be significant IMO.
I don't have any of the books by BK's former teacher Katherine Ramsland, but perhaps one of you does. It's kind of a shot in the dark, especially since page content can vary with different editions, but I wonder if by any chance there would be something interesting on page 118, say, of her book about the confessions of the BTK killer.
Pure speculation, but could be interesting if page 118 happened to be something about BTK's "hidey holes" or some other trick of his.