SPOILER - something that spoiled an otherwise excellent film
Okay, so Hayley's character Susan finds out 'backward' Georgie is really Martin.
She also learns it's highly probable he murdered his own father. Making Martin even more dangerous than simply a man who pretends to be retarded.
But guess what, after visting Martin's mother, Susan doesn't go straight to the police, she goes BACK HOME where crazy Martin is who would be already one step ahead and know Susan knows about him.
This made no sense and put Susan in a dangerous, self inflicted situation.
Better I think would have been if Susan's mother had discovered Georgie's real identity and Susan didn't know when she got back home.