“Now, how do you know that?” said the astonished Duke.
“It’s as plain as a pike-staff,” said Guerchard. “There must have been several burglars to move such pieces of furniture. If the soles of all of them had been covered with plaster, all the sweeping in the world would not have cleared the carpet of the tiny fragments of it. I’ve been over the carpet between the footprint and the window with a magnifying glass. There are no fragments of plaster on it. We dismiss the footprint. It is a mere blind, and a very fair blind too—for an examining magistrate.”
“I understand,” said the Duke.
“That narrows the problem, the quite simple problem, how was the furniture taken out of the room. It did not go through that window down the ladder. Again, it was not taken down the stairs, and out of the front door, or the back. If it had been, the concierge and his wife would have heard the noise. Besides that, it would have been carried down into a main street, in which there are people at all hours. Somebody would have been sure to tell a policeman that this house was being emptied. Moreover, the police were continually patrolling the main streets, and, quickly as a man like Lupin would do the job, he could not do it so quickly that a policeman would not have seen it. No; the furniture was not taken down the stairs or out of the front door. That narrows the problem still more. In fact, there is only one mode of egress left.”
“The chimney!” cried the Duke.
“You’ve hit it,” said Guerchard, with a husky laugh. “By that well-known logical process, the process of elimination, we’ve excluded all methods of egress except the chimney.”
He paused, frowning, in some perplexity; and then he said uneasily: “What I don’t like about it is that Victoire was set in the fireplace. I asked myself at once what was she doing there. It was unnecessary that she should be drugged and set in the fireplace—quite unnecessary.”
“It might have been to put off an examining magistrate,” said the Duke. “Having found Victoire in the fireplace, M. Formery did not look for anything else.”
“Yes, it might have been that,” said Guerchard slowly. “On the other hand, she might have been put there to make sure that I did not miss the road the burglars took. That’s the worst of having to do with Lupin. He knows me to the bottom of my mind. He has something up his sleeve—some surprise for me. Even now, I’m nowhere near the bottom of the mystery. But come along, we’ll take the road the burglars took. The inspector has put my lantern ready for me.”
As he spoke he went to the fireplace, picked up a lantern which had been set on the top of the iron fire-basket, and lighted it. The Duke stepped into the great fireplace beside him. It was four feet deep, and between eight and nine feet broad. Guerchard threw the light from the lantern on to the back wall of it. Six feet from the floor the soot from the fire stopped abruptly, and there was a dappled patch of bricks, half of them clean and red, half of them blackened by soot, five feet broad, and four feet high.