“Indeed, I am not laughing at you, Birts,” protested Humblethorne a little more warmly than he would have spoken if he had not been so nearly doing it. “That is a fairly exact description of the man who got into the house last night——” “Yes, through that little window,” interpolated Birts, anxious to remind Humblethorne that he had at any rate reasoned the crime out from that start. “What little window? Oh, in the pantry: I’d forgotten about that. No, he didn’t get in there.” “Not there! Why——” “That has nothing whatever to do with the case. I never really supposed it had,” interrupted Humblethorne decisively. “That might have got broken in a score of ways; there’s not the smallest evidence that any one got in through it, and there’s every reason to suppose that no one did.” “How did he get in then?” Birts was nettled at this drastic sweeping away of his one theory and spoke with the air of a man putting an unanswerable conundrum. “Through the drawing-room,” replied Humblethorne shortly. “Through the drawing-room!” repeated Birts incredulously. “But the shutters were all up; they hadn’t been touched either, for I looked at them myself when I got here.” “It is possible to open them from inside,” remarked Humblethorne gravely, “and that is the reason I am now looking for a pair of evening shoes. If I can find them, I know all I want to know about the man on whose story so much depends.” “Mr. Castle!” gasped Birts. “You don’t mean——” “I mean nothing,” broke in Humblethorne, irritated that he had been led on to say so much, “and take care you say nothing yet to any one of what I’ve been saying—not to any one.” “I’ll keep my mouth shut all right, sir, never fear,” said Birts with sudden sternness: he recognized that in the eyes of his superior he had allowed himself to be made a fool of by one of the criminals, and he was full of personal as well as professional resentment. “Good; I trust you, remember,” said Humblethorne, rising, “or I wouldn’t have told you so much until the chain of evidence was complete. Until it is, by the way, I think I’ll take charge of the weapon. I’m afraid we shan’t learn much from it, though: that kind of florid silver work is pretty hopeless for finger-prints. Pity it isn’t an ordinary smooth box; if it was, it could tell us all we most want to know.” He went over to the sheet, lifted it, and with great precautions not to interfere with any finger-prints which might be discoverable on it removed and wrapped up the cigarette box. “Now I’m off, Birts,” he said; “remember what I told you.” They moved off towards the door, Birts saying grimly, “I don’t think as I’m likely to forget.” “I may not be here to-morrow morning,” added Humblethorne, in a lower tone, “I’ve a few inquiries to put through, and they may take a little time.” “I can’t bring to mind any one about here who exactly fits that description you give me,” remarked Birts ruminatively; “let’s see——”