As the killer whistles, Comin' Through The Rye, a husband and wife are shot after being blackmailed. Evidence points to the neer-do-well son of a banker. The Stuarts' Butler told Philo Vance and DA Markham that he heard someone whistle and then shots. He was on the third floor and by the time he came down to the library Mr. Stuart was dead and Mrs. Stuart lived only long enough to say that the killer wanted $100,000.