The Slaves of Paris by Emile Gaboriau

When Mascarin spoke of suppressing the man who stood in his way as easily as if he was alluding to extinguishing a candle, he was not aware that there was one circumstance which considerably enhanced the difficulty of his task, for André had been forewarned, and this note of warning had been sounded on the day on which he had received that letter from Sabine, in which she spoke in such despairing terms of her approaching marriage, which she had been compelled to agree to to save the honor of her family. This feeling was strengthened by a long conversation he had had with M. de Breulh-Faverlay and the Viscountess de Bois Arden, in which it was unanimously decided that the Count and Countess de Mussidan were victims of some plot of which Henri de Croisenois was certainly one of the promoters. He had no conception on what side to look for the danger, but he had an instinctive feeling that it was impending. He prepared, therefore, to act on the defensive. It was not only his life that was in danger, but his love and his future happiness. M. de Breulh-Faverlay had also serious apprehensions for the safety of a man for whom he entertained so great a respect and regard.

"I would lay a heavy wager," said he, "that we have to do with some villainous blackmailers, and the difficulty of the business is, that we must do the work ourselves, for we dare not invite the aid of the police. We have no proof to offer, and the police will not stir a foot on mere suppositions, and we should not earn the thanks of those we are desirous of assisting if we called the attention of the law to certain acts in their past lives; for who can say what the terrible secret is, that some vile wretch holds over the heads of M. and Madame de Mussidan? And it is quite on the cards that the Count and the Countess might be compelled to join the blackmailers and oppose us. We must act with the greatest prudence and caution. Remember, that if you are out at night, you must avoid dark corners, for it would be the easiest thing in the world to put a knife into your back."