The old fellow shook his head. “So far as any one going out goes,” he said, “how do I know? My eyes are not so young as they were. But coming in! Why, I was back here! How could any one pass me in the light without my seeing them?” “But,” suggested Barrison, “while you were down at the street signaling the taxi, some one who had been hiding in the alley might have slipped in, mightn’t they?” Old Roberts hung his head, and his whole heavy body expressed dejection. “That’s what I keep saying to myself, sir!” he whispered. “Not that I think it’s likely—but—my eyes aren’t what they once were, and suppose the murderer was hiding there, and just waiting for a chance to get in?” “And how long, altogether, were you away?” Lowry spoke for the first time. “That’s easy, sir. I went out a few minutes after Mrs. Parry told me to send for the taxi, and I had just come back when Mr. Barrison here came out to ask me if I’d seen any one pass.” “That was just before the shooting,” Barrison said. “_Before_ the shooting. And you’re prepared to swear, Roberts, that no one came out of the theater after that?” “I am, sir!” The old man’s eyes, dim as they were, left no room for doubt; he was speaking the truth. “All right, Roberts. I’m sure you’ve told the truth, and Mr. Dukane shall be told so. I don’t believe you’ll lose your job. Just the same, I wish you hadn’t gone to hunt taxicabs at that particular moment.” As the two detectives walked away, Lowry said under his breath: “We’ve proved that no one left the theater by the stage door after the shooting, but we’ve proved that they might have done so by the communicating door. We’ve proved that Lynch was at his post for the whole evening up to the shooting, so that no one could have come in by that way before then; but, since he left it afterward, there is no reason to suppose that that some one could not have made their exit that way after the crime. In other words, my dear friend and colleague, while we can’t prove it, we can find a perfectly possible way for the murderer to have entered and an equally possible way for him, or her, to have departed.” “You think that—whoever it was—came in while Roberts was blundering up or down the alley?” “I see no other explanation. Barrison, you are not officially under me, but I respect your judgment, and I like your work. I should be obliged if you would take on such branches of this case as seem to lie in your way. You have been in it since—so to speak—its inception. You should have a line on many aspects of it that I couldn’t possibly get, coming into it as I must, from a purely and coldly official standpoint. I’ll expect you to do your darnedest on it, and help me in every way you can. Right?” “Right, sir.” The young detective’s tone was full of ardor. “Then good night to you. One moment. Did you notice the initial on this pistol, the one you picked up?” He produced it as he spoke.