“Let us call the murderer A. Well, A has reason to believe that Templeton has those diamonds, and he doesn’t know that he has already given them to Moss. He has seen Jim Webb go off to Frattenbury—probably found out that he was staying the night there. And he has seen Templeton go, too. He could easily find out if he was expected back late or not. Tom Gale knew it, Grayson knew it, Jim Webb knew it—they talked it over in the inn. And Mrs. Yates knew it—she told me she’d remarked about it to others. “Well, then, A, with this information, speculates that Templeton might leave the diamonds on board. Quite likely. It was a dark night and a lonely walk. He determines to take a chance on this. But he can’t do it till the coast is quite clear. That wouldn’t be till after closing time—ten o’clock. He waits about outside, probably in the garden, taking his stick with him. He may have armed himself with a knife—ah! that’s it, he took a tool of some sort—very likely an old dagger, as the doctor pointed out, to prise open any locks. Capital! “What next? As he stood there waiting, he lighted a cigar—being an inveterate smoker—from force of habit. He would hear the men come out of the inn at ten o’clock; he would hear Tom Gale walk off along the quay, and then all would be quiet, with a clear coast. “He goes down to the shore now. The dinghy is afloat. It’s much more simple to use her for his purpose than to run a canoe down to the water—and less noisy. He gets into the dinghy, laying his walking-stick down in the stern—a natural action, because the seat for the rower is well aft—pulls out to the yacht, gets on board and makes the dinghy fast. “Then he lights the lamp. That’s all right, because anyone seeing it would naturally conclude the owner is aboard. People knew he was sleeping there that night. And he begins to make his search. “But Templeton comes back sooner than A expected. A man doesn’t generally leave a house where he’s dining so early. But we know Templeton did. He sees the light on board, finds the dinghy has gone, and wonders what is up. Possibly he jumps to the conclusion that Jim Webb has come back after all. A canoe is lying there handy; he runs her down to the water and paddles aboard. “Meanwhile A, still smoking his cigar from force of habit, has burnt it down to the band; he flicks it off, or it drops off by itself. Then he hears Templeton coming aboard. He is caught in the act. “He has the tool or dagger, whatever it is, in his hand. Possibly his first impulse is to hide—behind the table. But Templeton comes into the cabin, and, for the moment, hesitates in astonishment. The folding table is between them—that prevents a struggle. And then the climax comes. A, either desperate at being discovered or acting on a murderous instinct for the sake of the jewels—he hadn’t found them, and both lockers were open, as we know—probably the former, reaches over the table and aims a blow at the unlucky Templeton—a blow which proves fatal.