Arlington Road

On his way home, Michael, a professor specializing in the history of terrorism, saves the life of a seriously injured boy.
He then meets the parents, Oliver and Cheryl, who live in his neighborhood. They sympathize. But Michael is intrigued by a plan he sees at Oliver's house. When he finds out that the latter was not educated in Kansas as he claims, Michael persuades himself that Oliver is hiding something and decides to investigate.
He then realizes that his neighbor had assumed the identity of a dead man years ago.