Some years after Christine and Léa started working for the family, Madame Léonie developed depression and the girls became the target of her mental illness. The abuse worsened to the point that she would slam the girls' heads against the wall. On the evening of Thursday, February 2, 1933, Monsieur Lancelin was supposed to meet Madame Léonie and Genevieve for dinner at the home of a family friend. Madame Léonie and Genevieve had been out shopping that day. When they returned home that afternoon, no lights were on in the house. The Papin sisters explained to Madame Lancelin that the power outage had been caused by Christine plugging in a faulty iron. Madame Lancelin became irate and attacked the sisters on the first-floor landing. Christine lunged at Genevieve and gouged her eyes out. Léa joined in the struggle and attacked Madame Lancelin, gouging her eyes out as ordered by Christine. Christine ran downstairs to the kitchen where she retrieved a knife and a hammer. She brought both weapons upstairs, where the sisters continued their attack. At some point one of the sisters grabbed a heavy pewter pitcher and used it to strike both Lancelin women on the head. Experts who later responded to the scene estimated that the attack lasted about 2 hours. Some time later, Monsieur Lancelin returned home to find the house dark. He assumed that his wife and daughter had left for the dinner party and proceeded to the party himself. When he arrived at his friend's home, he found that his family was not there, either. He returned to his residence with his son-in-law at approximately 18:30 - 19:00, where they discovered the entire house still dark except for a light in the Papin sisters' room. The front door was bolted shut from the inside, so they were unable to enter the house. The two men found this suspicious and went to a local police station to summon help from an officer. Together with the policeman they responded to the Lancelin home where the policeman made entry into the home by climbing over the garden wall. Once inside, he found the bodies of Madame Lancelin and her daughter Genevieve. They had both been bludgeoned and stabbed to the point of being unrecognizable. Madame Lancelin's eyes had been gouged out and were found in the folds of the scarf around her neck, and one of Genevieve's eyes was found under her body and another on the stairs nearby.