“Did you do it?” murmurs the dead-eyed, handsome multiple-murder suspect to the wide-eyed, credulous reporter who’s supposed to be there to interview him, but who actually has other goals in mind. The reporter, a real person named Michael Finkel who is played by Jonah Hill in the movie “True Story,” has enough presence of mind to observe that he should be asking Christian Longo (James Franco) that same question.