r Stangerson nor me, nor the concierges who are
in prison. Why have they not put me in prison, too, on account of my
revolver?"

Rouletabille had already opened the window and was examining the
shutters.

"Were these closed at the time of the crime?"

"And fastened with the iron catch inside," said Daddy Jacques, "and I am
quite sure that the murderer did not get out that way."

"Are there any blood stains?"

"Yes, on the stones outside; but blood of what?"

"Ah!" said Rouletabille, "there are footmarks visible on the path--the
ground was very moist. I will look into that presently."

"Nonsense!" interrupted Daddy Jacques; "the murderer did not go that
way."

"Which way did he go, then?"

"How do I know?"

Rouletabille looked at everything, smelled everything. He went down
on his knees and rapidly examined every one of the paving tiles. Daddy
Jacques went on:

"Ah!--you can't find anything, monsieur. Nothing has been found. And now
it is all dirty; too many persons have tramped over it. They wouldn't
let me wash it, but on the day of the crime I had washed the floor
thoroughly, and if the murderer had crossed it with his hobnailed boots,
I should not have failed to see where he had been; he has left marks
enough in Mademoiselle's chamber."

Rouletabille rose.

"When was the last time you washed these tiles?" he asked, and he fixed
on Daddy Jacques a most searching look.

"Why--as I told you--on the day of the crime, towards half-past
five--while Mademoiselle and her father were taking a little walk before
dinner, here in this room: they had dined in the laboratory. The next
day, the examining magistrate came and saw all the marks there were on
the floor as plainly as if they had been made with ink on white paper.
Well, neither in the laboratory nor in the vestibule, which were both
as clean as a new pin, were there any traces of a man's footmarks. Since
they have been found near this window outside, he must have made his way
through the ceiling of The Yellow Room into the attic, then cut his way
through the roof and dropped to the ground outside the vestibule window.
But--there's no hole, neither in the ceiling of The Yellow Room nor
in the roof of my attic--that's absolutely certain! So you see we know
nothing--nothing! And nothing will ever be known! It's a mystery of the
Devil's own making."

Rouletabille went down upon his knees again almost in front of a small
lavatory at the back of the vestib