“If it wasn’t she, then, who was it?”
“Well, both of you know that my suspicions finally centred upon this fellow Meadows, alias all the rest of it. I thought I had a pretty good case against him even before we knew anything about him at all; afterward it almost amounted to a foregone conclusion. And then Meadows apparently committed suicide. Well, that didn’t affect my case; if anything (and the circumstances being as they were) it was actually strengthened. But Meadows, it turned out, could hardly have committed suicide at all. He must have been murdered. How did that make things look?
“Now, this is where we jumped to the wrong conclusion, Inspector. At least I did, I can’t answer for you; I’ve never known what was really in your mind from the very beginning. Misled, intentionally or otherwise, by you, I practically assumed that the two murders had been committed by one and the same person—or if I didn’t actually assume that, I came so near it as automatically to wash out the idea that Meadows committed the first. We agreed that they must almost certainly be interdependent, and I accepted your very plausible theory that the strongest and most obvious motive for the second was that Meadows had been an actual eye-witness of the first. And that theory of course eliminated him from the list of suspects. At the same time you made out a very useful case against Vane for the double murder.
“And now I’m afraid we become a little personal.
“Thinking things over in bed last night, away from your magnetic influence, I was suddenly struck by this bright thought: why does Inspector Moresby go to such pains to plant in my mind the idea that both murders were committed by the same person, and to give me the impression that this is what he himself thinks? He’s a reticent sort of devil; he’s never volunteered any ideas of his own worth speaking of before; he knows that in a way we’re rivals here; the last person he’d want to help toward a solution is Roger Sheringham—why? And of course the answer to that came pat: because he wants to put me on the wrong track! He doesn’t think those murders were committed by the same person. On the contrary, he’s convinced they weren’t. How’s that, Inspector?”
The inspector laughed heartily. “No, no, Mr. Sheringham,” he said, shaking his head. “You do me an injustice, you do really. That was my honest opinion when I was talking to you last night. I had no doubt at all that Mrs. Vane and Meadows were murdered by the same person and I don’t mind admitting it.”
“Humph!” observed Roger, not altogether without scepticism. “And do you still think so?”
“I’m always open to conviction, I hope,” replied the inspector carefully. “Yes, go on, sir. This is very interesting.”
“Well, whether you really thought there were two murderers or whether you didn’t, my base suspicions of you did me one good turn: they biased me in favour of thinking so myself. So when I set out to pay a visit to Meadows’ lodgings this morning, I was already prepared to look for his murderer in somebody other than that of Mrs. Vane. Well, I made my investigations, I unearthed a few new facts which looked interesting but which I was blessed at the moment if I could make head or tail of, and I sat down after lunch to try to think the whole thing out.” Roger re-lit his pipe, which had gone out, and settled himself more comfortably in his chair.
“It wasn’t for some little time that a very simple question occurred to me, to which the answer began at last to put me on the right track. The question was this: what after all has happened to make it so impossible that Meadows should be the murderer of Mrs. Vane, as seemed so obvious before? And the answer, of course, was—nothing! Very well, then. Could I get any further with the second mystery by utilising my theory of the two agents to make Meadows the solution of the first?