I saw this movie about 8 years ago but it was about this band and some other people who all are trapped in some warehouse building and someone is going around killing everyone. Finally in the end it ends up the killer is a girl who is a friend and she is obsessed with one of the members in the band who she lets live. She tells him about what she did and how they can now be together. She is his #1 fan and in love with him but he does not feel the same and is kinda scared of her now, so after she gets he's not into her, she kills him to. I think it ends with her holding his dead body saying something about him never leaving her now. It's more of a indie movie I think, it was on some movie channel on cable.