SPOILERS! Two Easy Plot Fixes
All they had to do to explain why the girl didn't go to the police is have her temporarily mentally unhinged from the death of her parents. So she's too scared or not thinking straight and no one believes her. Show her seeing a psychiatrist at the beginning. And the ending, all they had to do was show the girl's grandparents and the original kidnapped boy's parents watching them play baseball together, instead of just the grandparents. Have him wave at them and they all wave back. At least then we'd know the parents were reunited with their son. It was still an entertaining movie, and the kids were good actors.
When you get up in the morning, how do you decide what shade of black to wear? (Shallow Grave)