I got a bit confused about the death, she was dropped off at the grandfather's house, so at what point was she back with the prospective adopting father for him to kill her? I might have to watch the last 20 mins again.
I can't make my mind up. It is probably a good thing that it just didn't turn out to be a standard whodunit where all was resolved neatly in the end. Nobody came out of it well including the police, which is probably realistic, but it didn't quite feel like the end. That scene where she met her old charges was cringeworthy.
Some good acting I thought; the young lad who played the son was very convincing.