“That, I am sure, cannot be true,” said I, thinking of the beautiful smiling face in the garden.
“Well, at least they gave that impression. However, we will suppose that they are an extraordinarily astute couple, who deceive everyone upon this point, and conspire to murder the husband. He happens to be a man over whose head some danger hangs—”
“We have only their word for that.”
Holmes looked thoughtful. “I see, Watson. You are sketching out a theory by which everything they say from the beginning is false. According to your idea, there was never any hidden menace, or secret society, or Valley of Fear, or Boss MacSomebody, or anything else. Well, that is a good sweeping generalization. Let us see what that brings us to. They invent this theory to account for the crime. They then play up to the idea by leaving this bicycle in the park as proof of the existence of some outsider. The stain on the windowsill conveys the same idea. So does the card on the body, which might have been prepared in the house. That all fits into your hypothesis, Watson. But now we come on the nasty, angular, uncompromising bits which won’t slip into their places. Why a cut-off shotgun of all weapons—and an American one at that? How could they be so sure that the sound of it would not bring someone on to them? It’s a mere chance as it is that Mrs. Allen did not start out to inquire for the slamming door. Why did your guilty couple do all this, Watson?”