It’s a cliché, but “more than you bargained for” documentaries are typically the best ones. Those films that feature a filmmaker on an odyssey quest for one piece of truth, but discovers something richer and more profound along the journey. Such is the case with what Mads Brügger‘s astonishing “Cold Case Hammarskjöld,” about an investigation into a mysterious murder that strikes a vein and the blood of discovery comes gushing. What begins as a look into a plane crash, and the consequent death of United Nations secretary-general Dag Hammarskjöld in the early 1960s, quickly turns into something much more transfixing: the confirmation of a conspiracy theory that has existed for more than five decades.