Mid-way through the movie, the titular killer assaults the police station as they attempt to kill Ally (Olivia Holt) and Jay (Mason Gooding), leaving Detective Shaw (Jordana Brewster) to confront them ...

Watching even a terrible horror movie can be great fun if there's a mystery to be solved - namely, the identity of a secret killer hiding in plain sight. The whodunnit is a timeless plot device ...