."

"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 c