At a quarter past eleven, shrill cries rang across the fifth floor of a lodging house on the Rue Croix-des-Petits-Champs. Neighbors heard: “Help! Murder!” Thuilard hastened to the door of Mariette Villain’s chamber; it was bolted fast. He forced it open. Behind the leaf of the door lay a man, who scrambled to his feet only to be seized by Thuilard. In the far corner of the room, two women, their hair disheveled and their garments soaked in blood, were no longer capable of defense. Geneviève Lougueux was already dead; Mariette still drew breath. The man was Philippe-François Debacker, whose household Mariette had abandoned several weeks prior.
Before taking up residence in this garret, Mariette had been Debacker’s shopgirl in Nantes. A native of Mechelen, he had served in the naval artillery before establishing himself in Brest. He had married in 1806 and fathered twelve children, all of whom were living at the time of the events. In 1814, he had moved his family to Nantes, opening a tailoring establishment that prospered. Then Mariette, scarcely sixteen years of age, was taken into his employ. Champagnac recounts that Debacker became enamored of her and, after less than three years, abandoned his wife and children to follow her.
The pair took refuge in Paris. Mariette passed as Debacker’s lawful wife, while the legitimate spouse languished in destitution with the children, wanting for the barest necessities of life, according to the chronicler. Champagnac records that, driven to despair, she ultimately cast herself down a well. The twelve children were still living at the time of the crime. Champagnac observes that the business in Nantes had promised a prosperous future; now, their mother and they lacked for daily bread, while Debacker lived in Paris with Mariette.
Following his wife’s death, Mariette urged Debacker to honor the promise of marriage he had pledged to her. He countered with perpetual evasions. On January 2, 1829, she declared to him that she was parting from him forever and vacated their lodgings. She took a modest room on the fifth floor of No. 21, Rue Croix-des-Petits-Champs, sharing it with her companion Geneviève Lougueux, known as Maria. According to Champagnac, Debacker took this rupture deeply to heart. He soon discovered that Mariette was receiving the attentions of Mocloury, a fellow tailor; suspicion swiftly curdled into jealousy. In that very house, on that very floor, he could still inquire after her whereabouts. Her departure had severed their shared life, yet it had not undone the proximity of those doors and landings where the tenants continually crossed paths.
In the Passage Véro-Dodat, Debacker encountered Mariette and Mocloury. Following a brief altercation, he struck Mariette across the face with such violence that she was left covered in blood. This public scene furnished a grave precedent that several witnesses could connect to the man who later appeared at the house on the Rue Croix-des-Petits-Champs.
On February 26, at about six in the morning, Debacker knocked at the door of the girl Durand, who dwelt upon the same landing as Mariette. He did not initially ask after his former mistress, but inquired instead where Geneviève Lougueux resided. The young woman, well aware of Debacker’s rancor toward Mariette, answered that her friend was away in the country. Debacker was not satisfied with this evasion. He went downstairs to confront the concierge, pressing him with questions. The porter informed him that Mariette had moved chambers and now occupied number 17. Debacker ascended the stairs once more; after that moment, the concierge saw him no more. Nearly five hours elapsed before the desperate screams of a quarter past eleven pierced the fifth floor.
At approximately eleven-fifteen, those screams summoned the neighbors to the landing. Thuilard heard them, rushed to the locked door, and wasted no time: he splintered it open. The man who was struggling to his feet behind the door had just struck down the two women. Thuilard overpowered him. Other lodgers arrived in turn. They found Mariette stretched upon the floor, Geneviève slumped over in a chair, both steeped in their own blood.
The promptest aid was rendered to both women, but Geneviève had sustained several mortal wounds and had already ceased to breathe. Mariette was still breathing. Standing upright, Debacker stared fixedly at the woman upon whom he claimed he had sought vengeance. Champagnac attributes these words to him: he was not yet satisfied, for Mariette still lived. She expired shortly thereafter. Whereupon Debacker drew from his pocket the knife he had turned upon the two women and dealt himself several thrusts to the chest.
When the police commissioner and the examining magistrate arrived, they saw to it that Debacker received surgical dressing before they inspected the victims. The post-mortem examination was conducted in his presence. Geneviève bore four wounds: one at the upper part of the left breast, two upon the neck, and one in the lumbar region. They had severed the lung and pierced the spinal cord. Mariette Villain had received six wounds, to her arms, her face, and her left breast. Debacker’s self-inflicted wounds were dangerous, yet not mortal. When he was fit to answer interrogations, he confessed to having committed the double homicide. He declared that despair and jealousy had armed his hand against Mariette, and that Geneviève, seeking to shield her companion, had been struck down in turn. By his own account, he had struck Geneviève without knowing what he was doing. When presented with the bloodied knife, he acknowledged it as his own, explaining that he had caused it to be sharpened on both edges because he wished to make an end of it all.
On June 6, 1829, Debacker stood trial before the Assize Court of the Seine. During the reading of the indictment, the chronicler describes him as by turns despondent, weeping, then motionless with a vacant, fixed stare. He notes that sweat beaded upon his brow, that his countenance changed color, and that he buried his head between his hands. At other times, he seemed entirely indifferent to the solemn drama unfolding about him, so frozen were his features. Interrogated by the court, Debacker admitted to the act, yet repudiated all premeditation. He asserted that upon entering Mariette’s chamber he had found her at work; she had purportedly laughed, retorting that the sewing had been brought to her by Mocloury. In his version of events, this reply threw him into a frenzy and caused him to lose his senses. He denied certain remarks reported by witnesses, notably that he had voiced regret at not having killed Mariette sooner. Thus, the confession of the act itself did not resolve the crucial matter the jury had to decide: whether the murder of Mariette had been premeditated.
When Mocloury was ushered into the courtroom, Debacker’s demeanor shifted abruptly. He reviled him, accused him of being the author of the entire tragedy, and cried out: “Monster! You brought this all to pass! It is you who have ruined me!” Then his hands sank onto his knees and tears welled in his eyes. The jealousy that Debacker invoked to explain his violence reappeared before the jury in the flesh of the rival whom he blamed for his undoing.
After two hours of deliberation, the jurors answered affirmatively to the charges of homicide and premeditation regarding Mariette. Concerning Geneviève, they likewise answered yes to the question of homicide, yet declared that Debacker had acted without intent. The distinction between the two victims was thus inscribed upon their verdict, and the prisoner was sentenced to death. He received his condemnation without betraying the slightest emotion, according to the account.
The double-edged knife, identified by Debacker before the magistrate, remained bound to his confession. The sentence was pronounced on June 6, 1829; Champagnac does not record whether he subsequently mounted the scaffold.