But it is pretty clear from all the clues, which are extremely unambiguous, that Marty's daughter, Audrey, was most likely sexually abused as a young girl and we see very deliberate echoes of the ritual murders reflected in the way her dolls were arranged. This cannot be an accident. She must be connected to the case somehow.
A further clue may appear in tonight's episode which may reinforce this fairly obvious notion. On a comment board I was reading somewhere tonight someone said to look at Audrey's painting which appears in a photograph at her mom's house.
While a bit subtle, you can unmistakably see that her painting contains black stars. Coincidence?