“That is what we ask ourselves. Why should it be? But later we have the incident of the wrist watch—which again shows us that time plays a very important part in the crime. We are now fast approaching the actual drama. It is half-past ten when Bella Duveen leaves, and by the evidence of the wrist watch we know that the crime was committed, or at any rate that it was staged, before twelve o’clock. We have reviewed all the events anterior to the murder, there remains only one unplaced. By the doctor’s evidence, the tramp, when found, had been dead at least forty-eight hours—with a possible margin of twenty-four hours more. Now, with no other facts to help me than those we have discussed, I place the death as having occurred on the morning of June 7th.” I stared at him, stupefied. “But how? Why? How can you possibly know?” “Because only in that way can the sequence of events be logically explained. _Mon ami___, I have taken you step by step along the way. Do you not now see what is so glaringly plain?” “My dear Poirot, I can’t see anything glaring about it. I did think I was beginning to see my way before, but I’m now hopelessly fogged.” Poirot looked at me sadly, and shook his head. “_Mon Dieu!___ But it is _triste!___ A good intelligence—and so deplorably lacking in method. There is an exercise most excellent for the development of the little grey cells. I will impart it to you—” “For Heaven’s sake, not now! You really are the most irritating of fellows, Poirot. For goodness’ sake, get on and tell me who killed M. Renauld.” “That is just what I am not sure of as yet.” “But you said it was glaringly clear?” “We talk at cross-purposes, my friend. Remember, it is two crimes we are investigating—for which, as I pointed out to you, we have the necessary two bodies. There, there, _ne vous impatientez pas!___ I explain all. To begin with, we apply our psychology. We find three points at which M. Renauld displays a distinct change of view and action—three psychological points therefore. The first occurs immediately after arriving in Merlinville, the second after quarrelling with his son on a certain subject, the third on the morning of June 7th. Now for the three causes. We can attribute No. 1 to meeting Madame Daubreuil. No. 2 is indirectly connected with her since it concerns a marriage between M. Renauld’s son and her daughter. But the cause of No. 3 is hidden from us. We have to deduce it. Now, _mon ami___, let me ask you a question; who do we believe to have planned this crime?” “Georges Conneau,” I said doubtfully, eyeing Poirot warily.