Xavier Dupont de Ligonnès, Accused of Murdering His Family, Disappeared

unsolved mysteries count xavier dupont de ligonnès and son — (Image credit: Courtesy of Netflix)

Trigger warning: this article contains descriptions of violence and a reference to suicide. One of the more horrific episodes of Netflix's Unsolved Mysteries reboot covers the case of Count Xavier Dupont de Ligonnès and the "House of Terror," as it was known at the time. The aristocratic French family—Xavier, his wife Agnès, and their children Arthur, Thomas, Anne, and Benoît—appeared to be happy, well-respected members of the community. But after a prolonged disappearance and a set of mysterious letters, police found the decomposing remains of the four children and Agnès underneath the boarded-up house. All had been drugged and then shot twice in the head as they slept. The family's two Labradors, which were heard howling around the potential time of the killings, were buried alongside the family.

Who is Xavier Dupont de Ligonnès?

Xavier, who became a count when his father died, had seemingly lived a life typical of the French aristocratic set. That is, until he wrote a long, rambling letter to relatives on behalf of his family that explained he was working for the United States DEA and that he and his family were going into witness protection and would not be contactable. Then, he disappeared—and he remains the main suspect in the murder of his family to this day.

Xavier was descended from French royalty. When his father died in early 2011, Xavier inherited a .22 rifle—but realized when handling his father's estate that there was no family money left. Xavier was already in dire straits financially, and his businesses had not been successful. It was later discovered that it was around this time that he learned how to shoot his father's gun and bought a silencer.

What happened to the Dupont de Ligonnès family?

The exact timeline of the murders is not clear, given that the family was discovered weeks after they were killed. The episode speculates that Arthur, Anne, Benoît, and Agnès were killed at roughly the same time on April 3-4 or 4-5, and Xavier's oldest biological son, Thomas, was killed shortly afterwards (the two reportedly went out for dinner on April 4 and barely spoke to each other).

Afterwards, Xavier took his car and traveled south. The last image of Xavier features him and a large bag—in which the episode speculates he carried the rifle—in Roquebrune-sur-Argens. The surrounding wilderness contains caves and abandoned mines, and police speculated that he might have killed himself. The area also has trains and ships that might have allowed him to unobtrusively make a getaway. No body was ever found.

What did the Unsolved Mysteries episode leave out?

There were a few interesting points missing from the episode. Agnès apparently spoke in an online forum (anonymously) that she was unhappy in her marriage—afraid and anxious of an "old-fashioned" husband: "The father is the head, he gives an order, we execute it without seeing to question or understand, period!"

She also noted that she was lacking in affection and friends, and that she was very worried about the family's money troubles.

france, nantes april 26, 2011 several hundred people take part in a march in nantes, western france, in memory of the five dupont de ligonnes members from the same family murdered in their nantes family house the bodies of the mother agnes dupont de ligonnes and her four children arthur, thomas, anne and benoit aged 13 to 20 years have been found in the garden of their house on april 21, 2011 the father, xavier dupont de ligonnes, is the prime suspect of the quintuple murder but it is not found yet the event started from the city center of nantes to reach the house of the tragedy flowers, candles and photos of children were placed before the house picture of the four children arthur, thomas, anne and benoit photo by alain denantesgamma rapho via getty images — Arthur, Thomas, Anne, and Benoît.

In addition, Xavier allegedly had a mistress in Paris. He may have financed his escape using his wife's jewelry, which was missing from the house. Shortly before the killings, he also bought quicklime, which was later found on top of the bodies in order to hasten their decomposition.

Second-oldest son Thomas' phone was used in the days following his disappearance, but the recipients remarked that the styling of the messages seemed unlike him. There are local sources who claim to have seen and spoke with Agnès in the days after her presumed death, but those were never confirmed.

A Reddit post also discusses a resurfaced blog, allegedly from Xavier's sister and brother-in-law, subtitled "Another point of view on the Dupont de Ligonnès case" in French, that discusses the possibility that Xavier did not commit the murders. Writes the Reddit user:

I went digging around and found a blog that was created by Xavier's family (his sister, mother, and brother-in-law). They seem convinced that he's completely innocent and that what he said in his letter about being an informant for the DEA is true.

I went in thinking it was complete BS (the letter had me rolling my eyes during the episode because I thought it was just that obvious of a lie), but then I found the family's blog and they managed to make me doubt things a bit.

It has not been confirmed that the blog is actually by members of Xavier's family.

Was Xavier ever found?

Several searches for Xavier were conducted near the place where he disappeared, primarily in 2011 and 2012. There have been reported and unconfirmed sightings of Xavier since he disappeared, including in Italy, and there was speculation he might be hiding with family members.

a picture showing benoit dupont de ligonnes, one of the five dupont de ligonnes family members murdered, has been set in front of their house, where they were discovered on april 21, on april 26, 2011 in the french western city of nantes, during a march in memory to the victims french authorities issued an international search alert on april 23 for murder suspect xavier dupont de ligonnes amid evidence that he carefully planned the killing of his wife and four children afp photo jean sebastien evrard photo credit should read jean sebastien evrardafp via getty images — A memorial outside the family’s home.

In 2015, a note was sent to a journalist at Agence France-Presse (AFP), allegedly from Xavier, on the back of what appeared to be a family photo featuring his two sons. The note read “I am still alive...From then until this hour.” It has never been confirmed whether the note is actually from Xavier; French prosecutors didn't comment on the incident.

Xavier Dupont de Ligonnès : une mystérieuse photo envoyée > http://t.co/Hpod8bP0mS pic.twitter.com/30FTRaXR8TJuly 24, 2015

In 2018, French police raided a monastery after a report that Xavier might be hiding there—but they determined that it was a monk who simply looked like him. In 2019, a French man was arrested in Scotland suspected to be Xavier based on a partial fingerprint, but was proven to be a completely different person.

If you have information about the Dupont de Ligonnès family, visit unsolved.com.

Katherine’s a contributing syndications editor at Marie Claire who covers fashion, culture, and lifestyle. In her role, she writes stories that are syndicated by MSN and other outlets. She’s been a full-time freelancer for over a decade and has had roles with Cosmopolitan (where she covered lifestyle, culture, and fashion SEO content) and Bustle (where she was their movies and culture writer). She has bylines in New York Times, Parents, InStyle, Refinery29, and elsewhere. Her work has also been syndicated by ELLE, Harper’s Bazaar, Seventeen, Good Housekeeping, and Women’s Health, among others. In addition to her stories reaching millions of readers, content she's written and edited has qualified for a Bell Ringer Award and received a Communicator Award.

Katherine has a BA in English and art history from the University of Notre Dame and an MA in art business from the Sotheby's Institute of Art (with a focus on marketing/communications). She covers a wide breadth of topics: she's written about how to find the very best petite jeans, how sustainable travel has found its footing on Instagram, and what it's like to be a professional advice-giver in the modern world. Her personal essays have run the gamut from learning to dress as a queer woman to navigating food allergies as a mom. She also has deep knowledge of SEO/EATT, affiliate revenue, commerce, and social media; she regularly edits the work of other writers. She speaks at writing-related events and podcasts about freelancing and journalism, mentors students and other new writers, and consults on coursework. Currently, Katherine lives in Boston with her husband and two kids, and you can follow her on Instagram. If you're wondering about her last name, it’s “I go to dinner,” not “Her huge ego,” but she responds to both.