Returning to his study, he at once rang up Mazeroux and, lowering his voice so as not to let it reach the next room, he said: 

“Is that you, Mazeroux?”

“Yes.”

“Has the Prefect placed you at my disposal?”

“Yes.”

“Well, tell him that I have sacked all my servants and that I have given you their names and instructed you to have an active watch kept on them.  We must look among them for Sauverand’s accomplice.  Another thing:  ask the Prefect to give you and me permission to spend the night at Hippolyte Fauville’s house.”

“Nonsense!  At the house on the Boulevard Suchet?”

“Yes, I have every reason to believe that something’s going to happen there.”

“What sort of thing?”

“I don’t know.  But something is bound to take place.  And I insist on being at it.  Is it arranged?”

“Right, Chief.  Unless you hear to the contrary, I’ll meet you at nine o’clock this evening on the Boulevard Suchet.”

Perenna did not see Mlle. Levasseur again that day.  He went out in the course of the afternoon, and called at the registry office, where he chose some servants:  a chauffeur, a coachman, a footman, a cook, and so on.  Then he went to a photographer, who made a new copy of Mlle. Levasseur’s photograph.  Don Luis had this touched up and faked it himself, so that the Prefect of Police should not perceive the substitution of one set of features for another.

He dined at a restaurant and, at nine o’clock, joined Mazeroux on the Boulevard Suchet.

Since the Fauville murders the house had been left in the charge of the porter.  All the rooms and all the locks had been sealed up, except the inner door of the workroom, of which the police kept the keys for the purposes of the inquiry.

The big study looked as it did before, though the papers had been removed and put away and there were no books and pamphlets left on the writing-table.  A layer of dust, clearly visible by the electric light, covered its black leather and the surrounding mahogany.

“Well, Alexandre, old man,” cried Don Luis, when they had made themselves comfortable, “what do you say to this?  It’s rather impressive, being here again, what?  But, this time, no barricading of doors, no bolts, eh?  If anything’s going to happen, on this night of the fifteenth of April, we’ll put nothing in our friends’ way.  They shall have full and entire liberty.  It’s up to them, this time.”

Though joking, Don Luis was nevertheless singularly impressed, as he himself said, by the terrible recollection of the two crimes which he had been unable to prevent and by the haunting vision of the two dead bodies.  And he also remembered with real emotion the implacable duel which he had fought with Mme. Fauville, the woman’s despair and her arrest.

“Tell me about her,” he said to Mazeroux.  “So she tried to kill herself?”