Uncle Peter?
The man gave off the most wonderful stranger-danger vibes in the beginning, and I'm sure he was most people's first (and perhaps only necessary) clue.
Despite being a total creeper it was his character I kept wondering about. When he asked how she was, was this more than some "funny uncle" line? Did he really care? Was he sorry?
After John turned on him so viciously, it made me wonder about his character.
At first, I almost bought the whole idea that neither the father or uncle were really there, solely because Peter seemed young enough to be Sarah's childhood memory.
Did anybody else get the idea the director was hinting a young-Peter might have been twisted/manipulated by his brother?