“Certainly. In spite of everything—the footprint in the flower bed, for example—I was still keeping before me the possibility of a woman being mixed up in it. It didn’t seem altogether probable, but I couldn’t afford to lose sight of the bare possibility. And it’s lucky I did, for it was just that which finally put me on the right track.”
“Good Lord!”
“Yes; I admit I was slow in the up-take, for the fact had been staring me in the face the whole time, and I never spotted it. You see, the key to the whole mystery was that there was a second woman in the library that night.”
“How on earth do you know that?” Alec asked in consternation.
“By the hair we found on the settee. I put it away in the envelope, you remember, and promptly forgot all about it, assuming it to have been one of Mrs. Plant’s. It struck me suddenly in the garden just now that it wasn’t anything of the sort; Mrs. Plant’s hair is very much darker. Of course that opened up an entirely new field for speculation.”
“Good Lord!”
“Yes, it is rather surprising, isn’t it?” Roger continued equably. “That set my brain galloping away like wildfire, I need hardly tell you; and five minutes later the whole thing became absolutely plain to me. I’m a little hazy about some of the details, of course, but the broad lines are clear enough.”
“You mean you guessed who the second woman was?”
“Hardly guessed. I knew at once who she must be.”
“Who?” Alec asked, with unconcealed eagerness.