Could Mr. Copperdock have committed the murder? It was quite possible. If he had left his shop a few minutes before five, he would have had plenty of time to reach the exit from Paddington station, plunge the knife into his victim, and be at the Cambridge Arms at five minutes past. But, if he were the criminal, a thousand puzzling questions presented themselves. How did he know that his victim would be arriving at Paddington at 4:55 that evening? Above all, why should Mr. Copperdock, the tobacconist, have any grudge against Mr. Pargent, the minor poet? And then again, Whyland was convinced that the murderer of Richard Pargent had been the murderer of James Tovey. But, at the moment when Tovey had been killed, Mr. Copperdock was in his sitting-room with his son and the murdered man’s daughter. The riddle appeared to be insoluble.