n Prevailles
had refused to reply to the questions put to him; but now, assisted by
his counsel, he pleaded a circumstantial alibi and maintained that he
was at the Folies-Bergere on the night of the murder.

As a matter of fact, the pockets of his dinner-jacket contained the
counterfoil of a stall-ticket and a programme of the performance, both
bearing the date of that evening.

"An alibi prepared in advance," objected the examining-magistrate.

"Prove it," said Prevailles.

The prisoner was confronted with the witnesses for the prosecution. The
young lady from the confectioner's "thought she knew" the gentleman with
the eyeglass. The hall-porter in the Rue de Berne "thought he knew" the
gentleman who used to come to see Jenny Saphir. But nobody dared to make
a more definite statement.

The examination, therefore, led to nothing of a precise character,
provided no solid basis whereon to found a serious accusation.

The judge sent for Ganimard and told him of his difficulty.

"I can't possibly persist, at this rate. There is no evidence to support
the charge."

"But surely you are convinced in your own mind, monsieur le juge
d'instruction! Prevailles would never have resisted his arrest unless he
was guilty."

"He says that he thought he was being assaulted. He also says that he
never set eyes on Jenny Saphir; and, as a matter of fact, we can find no
one to contradict his assertion. Then again, admitting that the sapphire
has been stolen, we have not been able to find it at his flat."

"Nor anywhere else," suggested Ganimard.

"Quite true, but that is no evidence against him. I'll tell you what we
shall want, M. Ganimard, and that very soon: the other end of this red
scarf."

"The other end?"

"Yes, for it is obvious that, if the murderer took it away with him, the
reason was that the stuff is stained with the marks of the blood on his
fingers."

Ganimard made no reply. For several days he had felt that the
whole business was tending to this conclusion. There was no
other proof possible. Given the silk scarf--and in no other
circumstances--Prevailles' guilt was certain. Now Ganimard's position
required that Prevailles' guilt should be established. He was
responsible for the arrest, it had cast a glamour around him, he had
been praised to the skies as the most formidable adversary of criminals;
and he would look absolutely ridiculous if Prevailles were released.

Unfortunately, the one and only indisp