n a manner at
once so bold and so unique that we were certain it could be the work
of but a single man--a rascal named Crochard, who calls himself also
'The Invincible'--a rascal who has given us very great trouble, but
whom we have never been able to convict. In this case, we had against
him no direct evidence; we subjected him to an interrogation and
found that he had taken care to provide a perfect alibi; so we were
compelled to release him. We knew that it would be quite useless to
arrest him unless we should find some of the stolen jewels in his
possession. He appeared as usual upon the boulevards, at the cafes,
everywhere. He laughed in our faces. For us, it was not pleasant; but
our law is strict. For us to accuse a man, to arrest him, and then to
be compelled to own ourselves mistaken, is a very serious matter. But
we did what we could. We kept Crochard under constant surveillance;
we searched his rooms and those of his mistress not once but many
times. On one occasion, when he passed the barrier at Vincennes, our
agents fell upon him and searched him, under pretence of robbing him.

"He was, understand well, not for an instant deceived. He knew
thoroughly what we were doing, for what we were searching. He knew
also that nowhere in Europe would he dare to attempt to sell a single
one of those jewels. We suspected that he would attempt to bring them
to this country, and we warned your department of customs. For we
knew that here he could sell all but the very largest not only almost
without danger, but at a price far greater than he could obtain for
them in Europe. We closed every avenue to him, as we thought--and
then, all at once, he disappeared.

"For two weeks we heard nothing--then came the story of this man
Drouet, killed by a stab on the hand. At once we recognised the work
of Crochard, for he alone of living men possesses the secret of the
poison of the Medici. It is a fearful secret, which, in his whole
life, he had used but once--and that upon a man who had betrayed
him."

M. Pigot paused and passed his hand across his forehead.

"We were at a loss to understand Crochard's connection with Drouet,"
M. Pigot continued. "Drouet, while a mere hanger-on of the cafes of
the boulevards, was not a criminal. Then came the death of that
creature Morel, in an effort to gain possession of this cabinet, and
we began to understand. We made inquiries concerning the cabinet; we
learned its history, and the secret