The Prostitutes' Ball

Detective Shane Scully responds to a call in the Hollywood hills at a once-immaculate mansion, the scene of an infamous murder twenty-five years prior. He discovers the remnants of a lavish pool party. The revelers have fled, leaving three dead bodies in their wake, all shot with the same gun. One is an acclaimed film producer. The other two, a pair of gorgeous women.
With his new partner, Sumner 'Hitch' Hitchens, Scully begins to investigate what looks to be an open-and-shut case: The women were hired prostitutes, and there's security video of an angry husband firing on all three. A simple case of brutal revenge. But nothing is ever as simple as it seems: There's a single spent bullet casing that doesn't match the rest.