Sergeant Mazeroux was asleep while the crime was committed, and the fact of the discovery of the turquoise in the safe.  All this is crushing, I admit.  Added to it,” he continued, “we have the terrible presumption that I had every interest in the removal of M. Fauville and his son, inasmuch as, if there is no heir of Cosmo Mornington’s in existence, I come into a hundred million francs.  Exactly.  There is therefore nothing for me to do, Monsieur le Prefet, but to go with you to the lockup or else—­”

“Or else what?”

“Or else hand over to you the criminal, the real criminal.”

The Prefect of Police smiled and took out his watch.

“I’m waiting,” he said.

“It will take me just an hour, Monsieur le Prefet, and no more, if you give me every latitude.  And the search of the truth, it seems to me, is worth a little patience.”

“I’m waiting,” repeated M. Desmalions.

“Sergeant Mazeroux, please tell Silvestre, the manservant, that Monsieur le Prefet wishes to see him.”

Upon a sign from M. Desmalions, Mazeroux went out.

Don Luis explained his motive.

“Monsieur le Prefet, whereas the discovery of the turquoise constitutes in your eyes an extremely serious proof against me, to me it is a revelation of the highest importance.  I will tell you why.  That turquoise must have fallen from my ring last evening and rolled on the carpet.

“Now there are only four persons,” he continued, “who can have noticed this fall when it happened, picked up the turquoise and, in order to compromise the new adversary that I was, slipped it into the safe.  The first of those four persons is one of your detectives, Sergeant Mazeroux, of whom we will not speak.  The second is dead:  I refer to M. Fauville.  We will not speak of him.  The third is Silvestre, the manservant.  I should like to say a few words to him.  I shall not take long.”

Silvestre’s examination, in fact, was soon over.  He was able to prove that, pending the return of Mme. Fauville, for whom he had to open the door, he had not left the kitchen, where he was playing at cards with the lady’s maid and another manservant.

“Very well,” said Perenna.  “One word more.  You must have read in this morning’s papers of the death of Inspector Verot and seen his portrait.”

“Yes.”

“Do you know Inspector Verot?”

“No.”

“Still, it is probable that he came here yesterday, during the day.”

“I can’t say,” replied the servant.  “M.  Fauville used to receive many visitors through the garden and let them in himself.”

“You have no more evidence to give?”

“No.”

“Please tell Mme. Fauville that Monsieur le Prefet would be very much obliged if he could have a word with her.”

Silvestre left the room.

The examining magistrate and the public prosecutor had drawn nearer in astonishment.