What's the title of this movie?

It's about the murderer, he had this birth defect and killed people and wore their skin as a mask. He comes out on Halloween. Then he has this sister, thats perfectly normal and that nobody knows of her. The girl is the daughter of the police man in town. Then the murderer chases her down into an abandoned building on night and she ends up killing her brother. She walks out of the building surrounded with cops. And she's wearing her brother's mask. Whats the title??