“Look here, sir,” he said. “I don’t in the least understand what you are driving at. I was at the hotel on that evening. I was dancing. I was enjoying myself very much. As for being frightened or guilty, I never felt less like it in my life. You tell me that you saw me. Well, you can take my word for it that I did not see you. Now, will you please tell me what all this means?”

“You did see me,” Mallett maintained. “I was standing within a few yards of you—just behind you, in fact.”

“Which of course explains why I didn’t see you.”

“You were looking in a glass to tie your bow-tie. It was at that moment that you saw me and looked—as I have said—frightened and guilty.”

“Looking in the glass to tie my tie. . . .” The young man mused a moment. “Good lord, so that was it?”

“Ah, so you remember now?”

“Certainly I remember—not seeing you, though. I may have, of course, but your face made absolutely no impression on me.”

“Then what was there to be frightened of?”

“I was frightened”, said Harper soberly, “of myself.”

“What?”

“Of my own appearance, I mean. That bow-tie. Don’t you remember. Inspector, the day we found him there—at Daylesford Gardens—I commented to you about his tie—what an ugly thing it was, and how badly tied? Well, when I looked in the glass, I got the shock of my life. Mine looked exactly like it. It suddenly brought it all back to me—that horrible swollen face and how his tongue stuck out from the corner of his mouth—ugh!”

Mallett was laughing.

“So that was why you looked so scared!” he chuckled. “Well, well! I always said you knew something about this case we didn’t know! What a lot of trouble you might have spared us!”

“Trouble? You don’t really mean that tie business was important?”

“About the most important thing in the whole case.”

“I don’t understand. Please tell me.”

Mallett had no objection. It was a minor point—now. He was relieved to find that this likeable young fellow was free from suspicion, and success had loosened his tongue.

“Your tie looked odd”, he explained, “because someone else had just tried to tie it for you—and done it very badly.”

“Yes,” said Harper, blushing a little in spite of himself.

“Ballantine’s looked odd for just the same reason.”

“But why should anyone tie it for him?”

“For the same reason that he put on his coat and trousers for him—to make him look like Ballantine.”

“After he was dead, do you mean?”

“Precisely.”

“Then what,” Harper asked with growing excitement, “what did he look like before he was killed?”

“He looked remarkably like a stout gentleman with a beard who once came to your office to take a furnished house in South Kensington.”