Guilty? We will likely never know. (Then again, I was sure that GSK/VR/ONS would never be caught, so I guess anything could happen.) I do believe it was one (or more) of the three in the house that night with JBR. No intruder.
My hunch is this: JBR's injuries & subsequent death were caused in that house, via the direct actions of either PR, JR, or BR (or some combo of the three). It could easily have been an accident and things snowballed as the R's had/have such an entitled, disgusting attitude of "we are rich Christians, nothing bad happens here". The one thing that absolutely rings true: a huge crime was committed in the coverup. Some one (as per the indictments) of the parents was aiding and abetting the other, or even acting in collusion. Perhaps a few things were being covered up, hence the specific nature of the recommended indictments, and the reluctance of the family to contact emergency services if it were just a simple accident. What were they hiding if that was the case?
Had this been any normal, non new-money, work-a-day folks, this death would (sadly) have been barely a blip on the public radar.