“Obviously because he wanted to leave all ways into or out of the library fastened on the inside, in order to further the idea of suicide.” “But why should he have gone back into the house at all? That’s what I can’t understand.” “Well,” Roger remarked very casually, “supposing he lived there?” “_What?_” “I said, supposing he lived there. He’d want to go up to bed, wouldn’t he?” “Good Lord, you’re surely not suggesting that somebody in the house murdered old Stanworth, are you?” Alec asked in horrified tones. Roger relit his pipe with some care. “Not necessarily, but you keep asking me why he should want to get back into the house, and I give you the most obvious explanation. As a matter of fact, I should say that he probably wanted to communicate with somebody inside before making his escape.” “Then you don’t think it was somebody from inside the house who killed Stanworth?” Alec asked with some relief. “Heaven only knows,” Roger replied laconically. “No, perhaps on second thoughts I don’t. We mustn’t forget that Jefferson couldn’t find those keys this morning. Unless that was a blind, by Jove! I never thought of that. Or he might have forgotten something important and wanted to get at the safe again, not realising that he’d put the keys back in the wrong pocket.” “I suppose,” Alec said slowly, “that Jefferson is the only person inside the house that you would suspect of having done it?” “No, I’m hanged if he is,” Roger retorted with energy. “Oh! Who else then?” “I’m suspecting everybody at present; put it like that. Everybody and everything within these four walls.” “Well, look here, don’t forget your promise, mind. No decisive steps to be taken without me, eh?” “Yes, but look here, Alec,” Roger said seriously, “you really mustn’t stand out unnecessarily if I might want to take steps that don’t altogether meet with your approval. We’re playing a very grave game, you know, and we can’t treat it as a joy-trip and only do the bits we like and leave out all the nasty part.” “Yes,” Alec said, a little reluctantly. “I see that. I won’t make a fuss about anything unnecessarily. But we must go on working together.” “Right!” Roger answered promptly. “That’s a bargain, then. Well, look here, there’s one thing we ought to have done earlier, but it quite slipped my memory. We must have a look for that possible second cartridge case. Personally I don’t believe there is one; I think there was one shot fired from each revolver. But it’s a possibility, and we ought not to overlook it.” “Rather a tall order, isn’t it? It might be anywhere in the whole grounds.” “Yes, but there’s only one place that it’s any use to search—the library. If we can’t find it there, we’ll give it up.” “Very well.” “Oh, Alexander,” Roger observed unhappily, as they strolled back to the library. “Alexander, we’re very terribly handicapped in this little problem, as Holmes would call it.” “In what way particularly?”