Two unusual films, both ending with unexpected twists and with more than a hint of film noir...
Donald Sutherland, as Inspector Carella, has to find the killer of a young girl whose cousin survived the attack. Their family's wholesome public image hides a very different reality, and Carella slowly untangles a complex web of incest and ugly fantasy in Blood Relatives.
More about Blood Relatives: http://www.imdb.com/title/tt0076313/
Kevin Costner, in Mr Brooks, plays restectable and highly successful businessman. He has an invisible friend with whom he shares the hobby of murder. They were about to call a halt to their activities when they acquire an unwanted side-kick (played by Dane Cook.) Demi Moore excels in her role as a detective faced with a string of artistically-arranged corpses.
More about Mr Brooks: http://www.imdb.com/title/tt0780571/