The movie is in a foreign language (European country?) takes place in an isolated area. A girl comes home after a while to stay with her mom and she brings her female bestfriend along (i remember the bff having a dark colored very short hair cut). Well as the movie goes on, there's a killer on the loose. Throughout the movie they make it clear that it's a man that's doing the VERY GOREY killings. There are a lot of twists in the movie, the biggest one being that the bff is actually the killer and at the end her friend finds out and she's then being hunted by her. Any help?