It was a flattering compliment.  Was it addressed only to Don Luis Perenna?  And had Lupin, the terrible, undaunted Lupin, no right to claim his share?  Was it possible to believe that M. Desmalions, in his heart of hearts, did not admit the identity of the two persons?

Nothing in the Prefect’s attitude gave any clue to his secret thoughts.  He was suggesting to Don Luis Perenna one of those compacts which the police are often obliged to conclude in order to gain their ends.  The compact was concluded, and no more was said upon the subject.

“Do you want any particulars of me?” asked the Prefect of Police.

“Yes, Monsieur le Prefet.  The papers spoke of a notebook found in poor Inspector Verot’s pocket.  Did the notebook contain a clue of any kind?”

“No.  Personal notes, lists of disbursements, that’s all.  Wait, I was forgetting, there was a photograph of a woman, about which I have not yet been able to obtain the least information.  Besides, I don’t suppose that it bears upon the case and I have not sent it to the newspapers.  Look, here it is.”

Perenna took the photograph which the Prefect handed him and gave a start that did not escape M. Desmalions’s eye.

“Do you know the lady?”

“No.  No, Monsieur le Prefet.  I thought I did; but no, there’s merely a resemblance—­a family likeness, which I will verify if you can leave the photograph with me till this evening.”

“Till this evening, yes.  When you have done with it, give it back to Sergeant Mazeroux, whom I will order to work in concert with you in everything that relates to the Mornington case.”

The interview was now over.  The Prefect went away.  Don Luis saw him to the door.  As M. Desmalions was about to go down the steps, he turned and said simply: 

“You saved my life this morning.  But for you, that scoundrel Sauverand—­”

“Oh, Monsieur le Prefet!” said Don Luis, modestly protesting.

“Yes, I know, you are in the habit of doing that sort of thing.  All the same, you must accept my thanks.”

And the Prefect of Police made a bow such as he would really have made to Don Luis Perenna, the Spanish noble, the hero of the Foreign Legion.  As for Weber, he put his two hands in his pockets, walked past with the look of a muzzled mastiff, and gave his enemy a glance of fierce hatred.

“By Jupiter!” thought Don Luis.  “There’s a fellow who won’t miss me when he gets the chance to shoot!”

Looking through a window, he saw M. Desmalions’s motor car drive off.  The detectives fell in behind the deputy chief and left the Place du Palais-Bourbon.  The siege was raised.

“And now to work!” said Don Luis.  “My hands are free, and we shall make things hum.”

He called the butler.

“Serve lunch; and ask Mlle. Levasseur to come and speak to me immediately after.”

He went to the dining-room and sat down, placing on the table the photograph which M. Desmalions had left behind; and, bending over it, he examined it attentively.  It was a little faded, a little worn, as photographs have a tendency to become when they lie about in pocket-books or among papers; but the picture was quite clear.  It was the radiant picture of a young woman in evening dress, with bare arms and shoulders, with flowers and leaves in her hair and a smile upon her face.