I always had a feeling that the custody papers were more for an alibi than actual custody. He is the father, so of course, custody would go to him upon the Mothers death as long as he can establish proof of a prior relationship with the child, provide a proper home, etc... and I haven’t heard of him and his family abusing or mistreating S, so yes they had a relationship, as far as we know he was a decent father to S, and yes he could provide a proper home so no reason not to grant him custody in the case of the Mother’s death. So the custody papers could have been to alibi why they didn’t commit the murders. Why would I kill HR Mr. Investigator, she had already signed over custody to me, so why would I harm her or her family? Or as another poster said, he couldn’t take a paternity test because he knew that S wasn’t his. And if he knew she wasn’t his, he obviously did not tell his family, I don’t see them being obsessed with a child that wasn’t blood related. My opinion only. Happy New Year everyone!