He replied: 

“Sergeant Mazeroux went to sleep in his chair and did not wake until Mme. Fauville returned, two hours later.”

There was a fresh silence, which evidently meant: 

“So, during the two hours when Sergeant Mazeroux was asleep, it was physically possible for you to open the door and kill the two Fauvilles.”

The examination was taking the course which Perenna had foreseen; and the circle was drawing closer and closer around him.  His adversary was conducting the contest with a logic and vigour which he admired without reserve.

“By Jove!” he thought.  “How difficult it is to defend one’s self when one is innocent.  There’s my right wing and my left wing driven in.  Will my centre be able to stand the assault?”

M. Desmalions, after a whispered colloquy with the examining magistrate, resumed his questions in these terms: 

“Yesterday evening, when M. Fauville opened his safe in your presence and the sergeant’s, what was in the safe?”

“A heap of papers, on one of the shelves; and, among those papers, the diary in drab cloth which has since disappeared.”

“You did not touch those papers?”

“Neither the papers nor the safe, Monsieur le Prefet.  Sergeant Mazeroux must have told you that he made me stand aside, to insure the regularity of the inquiry.”

“So you never came into the slightest contact with the safe?”

“Not the slightest.”

M. Desmalions looked at the examining magistrate and nodded his head.  Had Perenna been able to doubt that a trap was being laid for him, a glance at Mazeroux would have told him all about it.  Mazeroux was ashen gray.

Meanwhile, M. Desmalions continued: 

“You have taken part in inquiries, Monsieur, in police inquiries.  Therefore, in putting my next question to you, I consider that I am addressing it to a tried detective.”

“I will answer your question, Monsieur le Prefet, to the best of my ability.”

“Here it is, then:  Supposing that there were at this moment in the safe an object of some kind, a jewel, let us say, a diamond out of a tie pin, and that this diamond had come from a tie pin which belonged to somebody whom we knew, somebody who had spent the night in this house, what would you think of the coincidence?”

“There we are,” said Perenna to himself.  “There’s the trap.  It’s clear that they’ve found something in the safe, and next, that they imagine that this something belongs to me.  Good!  But, in that case, we must presume, as I have not touched the safe, that the thing was taken from me and put in the safe to compromise me.  But I did not have a finger in this pie until yesterday; and it is impossible that, during last night, when I saw nobody, any one can have had time to prepare and contrive such a determined plot against me.  So—­”

The Prefect of Police interrupted this silent monologue by repeating: