As soon as the police had been informed of the disappearance of Aubert, their suspicions had fallen on the Fenayrous in consequence of the request which Marin Fenayrou had made to the commissary of police to aid him in the recovery from Aubert of his wife's letters. But there had been nothing further in their conduct to provoke suspicion. When, however, the body was discovered and at the same time an anonymous letter received denouncing the Fenayrous as the murderers of Aubert, the police decided on their arrest. On the morning of June 8 M. Mace, then head of the Detective Department, called at their house. He found Fenayrou in a dressing-gown. This righteous avenger of his wife's seduction denied his guilt, like any common criminal, but M. Mace handed him over to one of his men, to be taken immediately to Versailles. He himself took charge of Madame, and, in the first-class carriage full of people, in which they travelled together to Versailles, she whispered to the detective a full confession of the crime. Mace has left us an account of this singular railway journey. It was two o'clock in the afternoon. In the carriage were five ladies and a young man who was reading La Vie Parisienne. Mme. Fenayrou was silent and thoughtful. "You're thinking of your present position?" asked the detective. "No, I'm thinking of my mother and my dear children." "They don't seem to care much about their father," remarked Mace. "Perhaps not." "Why?" asked M. Mace. "Because of his violent temper," was the reply. After some further conversation and the departure at Courbevoie of the young man with La Vie Parisienne, Mme. Fenayrou asked abruptly: "Do you think my husband guilty?" "I'm sure of it." "So does Aubert's sister." "Certainly," answered M. Mace; "she looks on the crime as one of revenge." "But my brother-in-law," urged the woman, "could have had no motive for vengeance against Aubert." Mace answered coldly that he would have to explain how he had employed his time on Ascension Day. "You see criminals everywhere," answered Madame. After the train had left St. Cloud, where the other occupants of the carriage had alighted, the detective and his prisoner were alone, free of interruption till Versailles should be reached. Hitherto they had spoken in whispers; now Mace seized the opportunity to urge the woman to unbosom herself to him, to reveal her part in the crime. She burst into tears. There was an interval of silence; then she thanked Mace for the kindness and consideration he had shown her. "You wish me," she asked, "to betray my husband?" "Without any design or intention on your part," discreetly answered the detective; "but by the sole force of circumstances you are placed in such a position that you cannot help betraying him."