KMC Forums - Can't remember the name....

Hello everyone, I just stumbled across this site as I was trying to find the name of a movie I saw awhile back. It's a B movie, but the storyline good. There's this teenage girl, who obviously suffers from a mental disorder, she has one friend, who's always trying to include her in things but she always declines saying she has to watch her brother. Well this girls father was a serial killer and tried to kill her and her younger brother in the past, (her brother was actually killed and she just thinks he's still there with her), and she thinks her father has come back to finish the job. All these people start turning up dead, and she's convinced it's the ghost of her father. And then her friend ends up being killed and the cop comes in and says oh no what did you do? And she blinks looks down and realizes she was the one who killed her friend and was the killer all along. I really would like to be able to find this movie again. Any help would be appreciated.