"A few nights ago our battalion had one of those unfortunate little contretemps that so often happen in war. A subaltern of ours, John Brinton by name, went out on patrol, and never returned. An exhaustive search in No Man's Land failed to discover his body; so we were reluctantly compelled to conclude that he was in German hands; whether alive or dead we don't know. There we have the first fact in my case. Now for the second.
"Two nights after that another of our subalterns was killed in a way which struck me as peculiar. I will not weary you with all the various little points that led me to believe that the bullet which killed him did not come from the trenches opposite; I will merely say that his position, his height, and the depth of the trench were the most obvious. And granted that my conclusions were correct, strange as it might appear at first sight, his death must have been caused at close quarters, possibly in the trench itself."
"Good Lord!" muttered the Adjutant, who was now listening with interest. "What do you mean?"
"Two facts, you see," went on Staunton quietly. "And they would have remained unconnected in my mind—Brinton's capture and Dixon's death—but for a small point of detail. Dixon's jacket was without the left regimental badge when his body was found. His servant knows he had them both earlier in the day. On the contrary, Brinton had lost his left regimental badge for some time. Am I interesting you?"
"Profoundly, thank you, sir." The man opposite smiled amiably.
"I'm glad of that; it's an interesting problem. You see the significance of that small point about the badge, the way in which it connects very intimately Brinton's capture and Dixon's death. So intimately, in fact, does it connect them, that one is almost tempted to assume that the man who killed Dixon was the man in possession of Brinton's uniform. Are you with me so far?"
"The evidence seems a trifle slight," remarked Jesson.
"Quite true; the evidence is very slight. But then, it often is. Everything up to date turns on the question of the badge. Let me reconstruct a possible—only possible, mark you—story, based on the supposition that my badge theory is correct. A German who speaks English perfectly is given a nice warm uniform taken from a captured British officer. Then he is told to go over to the British lines and see what he can find out. He comes one night; perfectly easy; no trouble; until walking along the front line he meets another officer—alone: an officer of the same regiment as that whose uniform he is wearing. Unavoidable; in fact, less likely to raise suspicion with the frequent changes that occur if he goes to the same regiment than if he went to another. But something happens: either the other officer's suspicions are aroused, or the German does not wish to be recognised again by him. The trench is quiet; an occasional rifle is going off, so he does the bold thing. He shoots him from point-blank range—probably with a Colt. As he stands there with the dead officer in front of him, waiting, listening hard, wondering if he has been heard, he sees the two badges on the officer's coat. So, being a cool hand, he takes off the left one, puts it on his own coat, and disappears for a time. Quite easy; especially when the trenches are old German ones."
"Really, Major, you seem to have made a speciality of detective fiction. As you said, I suppose your theory is possible."
Jesson spoke casually, but his eyes for the first time left the face of the man opposite him and roved towards the door. For the first time a sudden ghastly suspicion of the truth entered the Sapper's brain; and even as it did so he noticed that Staunton's revolver—the cleansing finished—pointed steadily at Jesson's chest.