Well when Ellie the policewoman was letting Susan go after interviewing her, Susan said why do you keep staring at me like that? Ellie said something about - "I can't believe you were in the house when all that was going on, and you didn't know" meaning when Susans' husband was abusing their daughter.
Just wondered if the same will be the case with Ellie and her husband, I think he may be very involved, and she was totally unaware. Also he is bald headed, so at a distance, when Susan thought she saw her estranged son in the boat dumping the body at night, maybe it was the other baldie, Ellies husband!!.
However she seems to have covered up the fact that her son and Danny were certainly not friends, lately at least.