Killing of the Dupont de Ligonnès Family and Disappearance of Its Patriarch

In April 2011, five members of the Dupont de Ligonnès family were killed in Nantes, in western France: a mother and her four children, aged 13 to 20. Their bodies were found buried beneath the patio of the family's home on 21 April, ten days after neighbors raised concerns that the house had been shuttered for more than a week while the mother's car sat untouched on the street outside. Autopsies determined that all five had been drugged and then shot while asleep with a .22-caliber rifle. The family's two dogs had also been killed and buried in the garden.

The household's father disappeared at the same time as the killings and has never been found. In the weeks beforehand, the family's affairs were wound down: the lease on the house was terminated, bank accounts were closed, and a final payment was made to the children's school. Investigators have reconstructed a timeline suggesting the mother and three of the children were killed on the night of 3-4 April, and that the eldest son, who had spent the evening of 5 April at a restaurant with his father, was the last of the five to die. In the days that followed, relatives and school administrators received calls, texts, and letters, purportedly from family members, describing a sudden relocation to Australia. A separate, unsigned letter sent to relatives instead claimed the family had entered a United States federal witness-protection program after covert work for an American drug-enforcement agency; no evidence establishes who wrote it.

Hotel and payment records placed the father in southern France in the two weeks after the killings. He was last captured on hotel surveillance video in Roquebrune-sur-Argens on 14 April, and his car was later found abandoned in the same town. He has not been seen since. French authorities have described him as the case's central suspect, but he has never been charged, and an Interpol notice seeking him as a witness remains outstanding. The Nantes prosecutor's office has said it has not reconsidered his status in the investigation and has leaned toward a theory that he died, possibly by suicide, adding that the case would close only by default if his remains are found and no other suspect emerges.

The search for him has continued for more than a decade without a confirmed result. Police and cave divers searched abandoned mines and forests in southern France in 2013; the effort was fruitless. In 2015, a walker found human bones and camping equipment in a forest near where the father was last seen, but DNA testing determined the remains belonged to an unidentified man. A 2018 raid on a monastery, prompted by reports of a resident monk resembling him, and a 2019 arrest at a Scottish airport based on a stolen passport, both proved to be cases of mistaken identity. A possible sighting was reported in Texas in 2020, and in March 2026 a Texas sheriff's office publicized decades-old photographs of him and appealed to the public for information. More than 800 leads have been logged since 2011, and the case remains unsolved.