One thing I've learned about those 'hunches' is that they're not all that reliable when it comes to abuse.
Time and time again a tearful mother, or tearful parents, say about an abuser: "We just didn't know. We thought "X" was a terrific guy. We thought the kids were perfectly safe with him/her." The woman on TV whose husband was selling kiddie




of him abusing their own eight year old daughter had no idea her husband was doing anything of the kind.
How many young male students have been abused by female teachers? How many times have stunned parents said, "We never saw anything wrong? We never saw any warning signs? We thought she was a good teacher?" Same thing for the priest scandal, for sports coaches everyone liked, for that nice older gentleman down the street. There just isn't a "type" of molester that can always be identified, and ruling out either of the adult Rs on the grounds of a hunch or feeling is something I don't think we can afford to do.
That said, I don't think actual molestation occurred Christmas night. I think something happened, and someone snapped, and whether it was PR or JR I think it did have something to do with the chronic abuse that seemed to show up in the autopsy.
If JBR had been a better reader, I'd wonder very much about that dictionary entry--if she was caught looking up that particular word by someone in her family who was abusing her, then the murder might have take place right there in the study! But from everything I've read looking up a word like that would have been beyond her very early reader skills.