“But that gentleman was here yesterday evening!  He was talking to my husband—­and so was that other gentleman,” she said, referring to Sergeant Mazeroux.  “You must question them, find out why they were here.  You understand that, if the turquoise belonged to one of them—­”

The insinuation was direct, but clumsy; and it lent the greatest weight to Perenna’s unspoken argument: 

“The turquoise was picked up by some one who saw me yesterday and who wishes to compromise me.  Apart from M. Fauville and the detective sergeant, only two people saw me:  Silvestre, the manservant, and Mme. Fauville.  Consequently, as Silvestre is outside the question, I accuse Mme. Fauville of putting the turquoise in the safe.”

M. Desmalions asked: 

“Will you let me see the necklace, Madame?”

“Certainly.  It is with my other jewels, in my wardrobe.  I will go for it.”

“Pray don’t trouble, Madame.  Does your maid know the necklace?”

“Quite well.”

“In that case, Sergeant Mazeroux will tell her what is wanted.”

* * * * *

Not a word was spoken during the few minutes for which Mazeroux was absent.  Mme. Fauville seemed absorbed in her grief.  M. Desmalions kept his eyes fixed on her.

The sergeant returned, carrying a very large box containing a number of jewel-cases and loose ornaments.

M. Desmalions found the necklace, examined it, and realized, in fact, that the stones did not resemble the turquoise and that none of them was missing.  But, on separating two jewel cases in order to take out a tiara which also contained blue stones, he made a gesture of surprise.

“What are these two keys?” he asked, pointing to two keys identical in shape and size with those which opened the lock and the bolt of the garden door.

Mme. Fauville remained very calm.  Not a muscle of her face moved.  Nothing pointed to the least perturbation on account of this discovery.  She merely said: 

“I don’t know.  They have been there a long time.”

“Mazeroux,” said M. Desmalions, “try them on that door.”

Mazeroux did so.  The door opened.

“Yes,” said Mme. Fauville.  “I remember now, my husband gave them to me.  They were duplicates of his own keys—­”

The words were uttered in the most natural tone and as though the speaker did not even suspect the terrible charge that was forming against her.

And nothing was more agonizing than this tranquillity.  Was it a sign of absolute innocence, or the infernal craft of a criminal whom nothing is able to stir?  Did she realize nothing of the tragedy which was taking place and of which she was the unconscious heroine?  Or did she guess the terrible accusation which was gradually closing in upon her on every side and which threatened her with the most awful danger?  But, in that case, how could she have been guilty of the extraordinary blunder of keeping those two keys?