“Just an accidental observation. He carries his fountain pen in his right-hand waistcoat pocket. You and I carry ours in the left pocket, so as to get at it easily with our right hands. He uses his left hand to take it from his pocket, and then he passes the pen to his right hand before he uses it. You see he uses his arm in taking it out, and he’s left-armed. That’s absolutely conclusive to my mind, and I didn’t want to run any chance of arousing suspicion by going through the whole programme. I think we’ve got our man.”
“That was pretty cute. I was watching him, but I didn’t spot the thing, although I was on the look-out for it.”
“It was just a bit of luck. Nothing to boast about.”
Douglas considered for a time.
“Well, where do we stand? Motive? He’s hard up and lost a lot at cards. Opportunity? He was wandering about the house late that night. Besides, his room is close to the one the Talisman was in. He’s left-armed—the type we’re looking for. He went up to town next morning—possibly to get the thing out of the house for fear of a search, even if he didn’t dispose of it in some way then—pawning or some such business. And, by the way, he’s got lamed in some way. I wonder if there is a man-trap after all, and he got mixed up in it slightly.”
Westenhanger listened to this catalogue with a gloomy face.
“There isn’t an atom of real proof in the whole lot. We could never satisfy anyone on the strength of that stuff alone. I’d never mention a word to anyone about it, Douglas; because we must have definite proof. And I don’t quite see our next move.”
“Watch him, and keep on watching, on the chance of something turning up, I suppose.”
“It’s a poor chance,” said Westenhanger.
That idea remained with him for the rest of the day. The step-by-step process of elimination had been carried through with complete success; but it was useless to pretend to himself that the result was conclusive evidence. At the best it became a case of “Not Proven”: a moral certainty, perhaps, but nothing more. Something further was needed to establish the identity of the culprit beyond doubt. And the more he puzzled over the problem, the less chance could he see of bringing the thing home. One might devise a scheme for trapping a fellow-guest; but how could one out-manœuvre a man working on his own ground with complete knowledge of all the possibilities of the environment?