Ripped off Inkubus (2011)
...but at the same is a much better movie. Inkubus has essentially the same plot: skeleton crew on the last shift of a police station experiences hauntings and whatnot from a murderous supernatural entity. I tried searching online but surprisingly nobody else has commented on the striking resemblance.
Though to be fair I don't know how Inkubus ended, despite the awesome potential it couldn't hold my interest.