"Why," answered Tignol slowly, while his shrewd eyes twinkled, "I—I'd have cussed a little and—had a couple of drinks and—come back to Paris."
Coquenil sat silent frowning. "I wasn't much better. After that first day I was ready to drop the thing, I admit it, only I went for a walk that night—and there's a lot in walking. I wandered for hours through that nice little town of Brussels, in the crowd and then alone, and the more I thought the more I came back to the same idea, he can't be a wood carver!"
"You couldn't prove it, but you knew it," chuckled the old man.
Coquenil nodded. "So I kept on through the second day. I saw more people and asked more questions, then I saw the same people again and tried to trip them up, but I didn't get ahead an inch. Groener was a wood carver, and he stayed a wood carver."
"It began to look bad, eh?"
Coquenil stopped short and said earnestly: "Papa Tignol, when this case is over and forgotten, when this man has gone where he belongs, and I know where that is"—he brought his hand down sideways swiftly—"I shall have the lesson of this Brussels search cut on a block of stone and set in my study wall. Oh, I've learned the lesson before, but this drives it home, that the most important knowledge a detective can have is the knowledge he gets inside himself!"
Tignol had never seen M. Paul more deeply stirred. "Sacré matin!" he exclaimed. "Then you did find something?"
"Ah, but I deserve no credit for it, I ought to have failed. I weakened; I had my bag packed and was actually starting for Paris, convinced that Groener had nothing to do with the case. Think of that!"
"Yes, but you didn't start."
"It was a piece of stupid luck that saved me when I ought to have known, when I ought to have been sure. And, mark you, if I had come back believing in Groener's innocence, this crime would never have been cleared up, never."