It is possible but I just don't see it. PR valued JB and got personal satisfaction when JB won beauty pageants. Why brutally murder her? It makes no sense. PR was not psychotic and she would have to be to have done it all like you say. I think there is another explanation, such as: BR delivers the head blow, parents hear the loud scream and discover what has happened. Parents decide to cover up for what BR has done. Both parents are involved in the staging but the most important and effective staging of all is done by JR, which is the garrote. It is their trump card that can be played at anytime: look at that. You know we couldn't have done that.
IMO JR became involved very late, after the note and after JonBenet was already dead.
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