ness,"
said M. Formery gravely.

"Perhaps Guerchard will be able to throw a little more light on it,"
said the Duke.

M. Formery frowned and said, "Yes, yes. Guerchard is a good assistant
in a business like this. A little visionary, a little
fanciful--wrong-headed, in fact; but, after all, he IS Guerchard. Only,
since Lupin is his bugbear, he's bound to find some means of muddling
us up with that wretched animal. You're going to see Lupin mixed up
with all this to a dead certainty, your Grace."

The Duke looked at the signatures on the wall. "It seems to me that he
is pretty well mixed up with it already," he said quietly.

"Believe me, your Grace, in a criminal affair it is, above all things,
necessary to distrust appearances. I am growing more and more confident
that some ordinary burglars have committed this crime and are trying to
put us off the scent by diverting our attention to Lupin."

The Duke stooped down carelessly and picked up a book which had fallen
from a table.

"Excuse me, but please--please--do not touch anything," said M. Formery
quickly.

"Why, this is odd," said the Duke, staring at the floor.

"What is odd?" said M. Formery.

"Well, this book looks as if it had been knocked off the table by one
of the burglars. And look here; here's a footprint under it--a
footprint on the carpet," said the Duke.

M. Formery and the inspector came quickly to the spot. There, where the
book had fallen, plainly imprinted on the carpet, was a white
footprint. M. Formery and the inspector stared at it.

"It looks like plaster. How did plaster get here?" said M. Formery,
frowning at it.

"Well, suppose the robbers came from the garden," said the Duke.

"Of course they came from the garden, your Grace. Where else should
they come from?" said M. Formery, with a touch of impatience in his
tone.

"Well, at the end of the garden they're building a house," said the
Duke.

"Of course, of course," said M. Formery, taking him up quickly. "The
burglars came here with their boots covered with plaster. They've swept
away all the other marks of their feet from the carpet; but whoever did
the sweeping was too slack to lift up that book and sweep under it.
This footprint, however, is not of great importance, though it is
corroborative of all the other evidence we have that they came and went
by the garden. There's the ladder, and that table half out of the
window. Still, this footprint may turn out useful, after a