“What would be your opinion?”

“There would be an undeniable connection between that person’s presence in the house and the two crimes that had been committed.”

“Consequently, we should have the right at least to suspect the person?”

“Yes.”

“That is your view?”

“Decidedly.”

M. Desmalions produced a piece of tissue paper from his pocket and took from it a little blue stone, which he displayed.

“Here is a turquoise which we found in the safe.  It belongs, without a shadow of a doubt, to the ring which you are wearing on your finger.”

Don Luis was seized with a fit of rage.  He half grated, through his clenched teeth: 

“Oh, the rascals!  How clever they are!  But no, I can’t believe—­”

He looked at his ring, which was formed of a large, clouded, dead turquoise, surrounded by a circle of small, irregular turquoises, also of a very pale blue.  One of these was missing; and the one which M. Desmalions had in his hand fitted the place exactly.

“What do you say?” asked M. Desmalions.

“I say that this turquoise belongs to my ring, which was given me by Cosmo Mornington on the first occasion that I saved his life.”

“So we are agreed?”

“Yes, Monsieur le Prefet, we are agreed.”

Don Luis Perenna began to walk across the room, reflecting.  The movement which the two detectives made toward the two doors told him that his arrest was provided for.  A word from M. Desmalions, and Sergeant Mazeroux would be forced to take his chief by the collar.

Don Luis once more gave a glance toward his former accomplice.  Mazeroux made a gesture of entreaty, as though to say: 

“Well, what are you waiting for?  Why don’t you give up the criminal?  Quick, it’s time!”

Don Luis smiled.

“What’s the matter?” asked the Prefect, in a tone that now entirely lacked the sort of involuntary politeness which he had shown since the commencement of the examination.

“The matter?  The matter?—­”

Perenna seized a chair by the back, spun it round and sat down upon it, with the simple remark: 

“Let’s talk!”

And this was said in such a way and the movement executed with so much decision that the Prefect muttered, as though wavering: 

“I don’t quite see—­”

“You soon will, Monsieur le Prefet.”

And, speaking in a slow voice, laying stress on every syllable that he uttered, he began: 

“Monsieur le Prefet, the position is as clear as daylight.  Yesterday evening you gave me an authorization which involves your responsibility most gravely.  The result is that what you now want, at all costs and without delay, is a culprit.  And that culprit is to be myself.  By way of incriminating evidence, you have the fact of my presence here, the fact the door was locked on the inside, the fact that