Credo (2008)

A modern supernatural horror film that explores the dark side of the human psyche, and the terror in facing up to one's darkest fears. Set in London, England, the film begins with a group of theological students who decide to test their faith by proving the existence of Hell. Following their ritualistic summoning of a demon, the students are all found dead, apparently by suicide. Years later, a group of five final-year students are evicted from their student digs and break into the now abandoned Catholic halls of residence for the weekend, only to discover that they're not alone.