I can think of one thing the Rs knew about JW that would have seriously decreased the likelihood of him easily winning custody -- he, as he has now been accused, was alleged to have had sex with HR when she was a minor.
Is there anything to say that they do not go there first? One idea that has been thrown out was that KR went to CRSRs house early in the morning to shower. It could have been to prevent him from coming onto the scene while the murders were occurring.