Build a movie plot around this: What do the police find in Bruno's hand? A lighter.
A:
Amateur Tennis star Guy Haines (Farley Granger) wants to divorce his vulgar and unfaithful wife Miriam (Laura Elliott), so he can marry the elegant and beautiful Anne Morton (Ruth Roman), daughter of a senator (Leo G. Carroll). While on a train to meet Miriam, Haines encounters Bruno Anthony (Robert Walker), a pushy stranger who recognizes Guy from gossip items in the newspapers and wants to discuss his marital problems. During lunch in Bruno's compartment, Bruno tells Guy about his idea for the perfect "criss-cross" murder(s): he will kill Miriam, and in exchange Guy will kill Bruno's father. Since they are unconnected strangers, there is no identifiable motive for the crimes, and therefore no suspicion from the police. Guy hurriedly departs the compartment, but leaves Bruno thinking he has agreed to the deal. Guy accidentally leaves his cigarette lighter behind, and Bruno pockets it. Guy meets Miriam at her work, where she decides to call off the divorce and play the Washington political wife. Guy threatens Miriam, then calls Anne and tells her he wants to "strangle" Miriam.Bruno arrives in Guy's hometown and follows Miriam and her two beaux to an amusement park, where he strangles her to death. Guy's alibi a college professor who was inebriated when they met cannot remember their meeting on the train. Guy's chances of being implicated increase when Bruno appears repeatedly to remind Guy that he is now obliged to kill Bruno's father.Bruno sends Guy the keys to his house, a map to his father's room, and a pistol. Soon after, Bruno appears at a party at Senator Morton's house and hobnobs with the guests, much to Guy's apprehension and Anne's increasing suspicion. Using another guest, he demonstrates how to strangle someone while preventing them from screaming; while doing this he sees Anne's younger sister Barbara (Patricia Hitchcock). Her eyeglasses and resemblance to Miriam trigger a flashback, and Bruno really begins to strangle the guest. After a moment he faints, and the frightened party guests pull him...