“But his left-handedness.”

“You were yourself struck by the nature of the injury as recorded by the surgeon at the inquest. The blow was struck from immediately behind, and yet was upon the left side. Now, how can that be unless it were by a left-handed man? He had stood behind that tree during the interview between the father and son. He had even smoked there. I found the ash of a cigar, which my special knowledge of tobacco ashes enables me to pronounce as an Indian cigar. I have, as you know, devoted some attention to this, and written a little monograph on the ashes of 140 different varieties of pipe, cigar, and cigarette tobacco. Having found the ash, I then looked round and discovered the stump among the moss where he had tossed it. It was an Indian cigar, of the variety which are rolled in Rotterdam.”

“And the cigar-holder?”

“I could see that the end had not been in his mouth. Therefore he used a holder. The tip had been cut off, not bitten off, but the cut was not a clean one, so I deduced a blunt penknife.”