"Follow that motor bus, driver, at fifty yards' distance."
"Is it Florence Levasseur?" asked Mazeroux.
"Yes."
"A nice thing!" growled the sergeant. And, yielding to a sudden outburst: "But, look here, Chief, don't you see? Surely you're not as blind as all that!"
Don Luis made no reply.
"But, Chief, Florence Levasseur's presence in the nursing-home proves as clearly as A B C that it was she who told the manservant to bring me that threatening letter for you! There's not a doubt about it: Florence Levasseur is managing the whole business.
"You know it as well as I do. Confess! It's possible that, during the last ten days, you've brought yourself, for love of that woman, to look upon her as innocent in spite of the overwhelming proofs against her. But to-day the truth hits you in the eye. I feel it, I'm sure of it. Isn't it so, Chief? I'm right, am I not? You see it for yourself?"
This time Don Luis did not protest. With a drawn face and set eyes he watched the motor bus, which at that moment was standing still at the corner of the Boulevard Haussmann.
"Stop!" he shouted to the driver.
The girl alighted. It was easy to recognize Florence Levasseur under her nurse's uniform. She cast round her eyes as if to make sure that she was not being followed, and then took a cab and drove down the boulevard and the Rue de la Pépinière, to the Gare Saint-Lazare.