“As soon as it’s struck ten—or thereabouts—keep your eye fixed on the upper window in the ‘Mariner’s Arms.’ There may be a light in the room. Don’t take any notice of that. But directly you see the flash of a red light in the window, get into the canoe and paddle ashore. Make a bit of noise about it. Leave the canoe in the water—the tide will be flowing—and make the painter fast to one of the posts you will find—well up the little bank. Then light your bicycle lamp and ride off—back to Frattenbury. I shan’t want you any more. If there’s anybody about, sing out ‘Good night’ to them—let ’em see you’re going off. You understand?” “I’ll do it, sergeant.” “That’s all, then. Good night, Major, if I don’t see you again. I’ll drop in,” he added to the superintendent, “before I go back to Marsh Quay. I’ve got a little job first. And I want this walking-stick.” He went out, carrying the stick he had found in the dinghy. CHAPTER VI Colson is Baffled Colson walked away from the police station till he came to a shop. It was Sunday and, of course, the shutters were up, but he rang the bell at the side door. It was opened by the proprietor, a thin, sandy-haired man, who shook hands with the detective. “Good afternoon, Mr. Colson,” he said, “come in, won’t you? We were just sitting down to tea. The wife will be pleased, I’m sure, if you’ll join us.” “No, thank you, Mr. Blake. I’m sorry to disturb you. But I want you to do something for me—if you will?” Blake looked at him with interest. “Anything about this murder at Marsh Quay?” he asked. “I heard you were down there.” “Now, look here, Mr. Blake, you and I know one another pretty well. Don’t you ask me any questions about that, please. I believe you’re a discreet man, or I shouldn’t have come to you. Will you hold your tongue about it? About what I’m going to ask you?” “Of course I will, Mr. Colson.” “Very well. I want you to sell me a walking-stick—on a Sunday. Can we go into your shop?” “Certainly. Come along.” He led the way into the shop, and turned on the electric light. Whereat it was obvious that Mr. Blake dealt in tobacco, and those other articles which generally characterise a tobacconist’s trade. “What sort of a stick do you want?” “One exactly like this—if you’ve got one.” Blake took the stick in his hand and examined it carefully. “You don’t know that stick, I suppose? You haven’t seen it before?” asked Colson. “Can’t say I have. It’s ordinary enough, eh? With a Swiss ferrule, too. Might have been bought in Switzerland, and might not. We keep a few of these ferrules now—some of our customers prefer them. Let’s see—it ought to be easy to find one like it.” A bundle of sticks was laid on the counter. Presently one was found very closely resembling that brought by Colson. “All right,” he said, “this will do—if you can put another ferrule on it.”