The Most Compelling ‘Unsolved Mysteries’ Fan Theories About The ‘House Of Terror’ Episode

Netflix’s Unsolved Mysteries revival appears to be a hit, given that the show landed in the platform’s Top 10 list two weeks ago and shows no sign of losing audience interest. The series mixes up the old format slightly, mostly by going hostless and doing deep dives into one mystery per episode, but it keeps an invaluable feature — asking anyone with knowledge of these cases to reach out at I wondered whether keeping that signature touch might prove even more useful in 2020 than it did in the 1990s. After all, Michelle McNamara started investigating the Golden State Killer case on an Internet message board, the Internet can help resurface darkness for the greater good. Well, it hasn’t taken long for the clues to start flowing in.

Co-creator and executive producer Terry Dunn Meurer recently told Variety that the show’s received at least 2,000 tips so far. A very small percentage of those tips will be credible ones, but some of them could lead to cracking cases that have already captivated viewers around the globe. Netflix has also decided to up the odds by hopping onto Reddit in an effort to get the train rolling even faster. On the Unsolved Mysteries subreddit, the streaming giant posted a link to Google Drive full of evidence (case files, interviews, and video clips) that didn’t make it on air. Theories are brewing for the Rey Rivera case, and it’s also happening regarding an allegedly homicidal French count.


The episode in question, “House Of Terror,” crosses the Atlantic to lift the veil on the gruesome Dupont de Ligonnès murders that took place in Nantes, France. The prime suspect, a French count (Xavier Dupont de Ligonnès) remains on the run and accused of murdering his wife, four children (ranging in age from 13 to 21), and two Labrador Retrievers in April 2011. The bodies of these five human (all killed, apparently execution style, with a .22 rifle) and two animal victims were discovered buried underneath the house’s patio. Authorities believe the murder happened two weeks prior to discovery, and Xavier Dupont de Ligonnès had apparently vanished into thin air.

Where on earth could a French count have disappeared to without a trace? Police scoured caves in 2012, and in 2019, a man that physically resembled the Dupont de Ligonnès was arrested in Glascow, Scotland but later ruled out following a DNA test.

The Netflix series already speculated that Xavier was secretly a DEA agent or had even lost all of his money before killing his family, and Reddit has other theories. Here are the most intriguing ones:

Theory #1: Xavier Dupont de Ligonnès Didn’t Act Alone

A Reddit user named dnrexy finds it hard to accept that — despite no mention by French authorities of other suspects or alleged accomplices — that Xavier could have killed his entire family (and the dogs) without assistance. The idea that he couldn’t have acted on his own might be disproved by the traces of sleeping medication reportedly found in the childrens’ bodies, but this theory’s still worth reading:

“A man in his 50’s with supposedly a bad back moving 4 dead bodies worth of dead weight and two dogs outside. Placing them in trash bags and burying them the way he did is close to impossible to do alone. Not to mention the organizational aspect of the whole thing. You mean to tell me he found a long rifle when his dad passed away and all of a sudden he becomes a criminal mastermind? I believe he hired professional help from somebody. Someone helped him coordinate those murders and helped him get away.”

Theory #2: Xavier Dupont de Ligonnès Studied The Methods Of An Infamous U.S. Serial Killer

Xavier’s alleged acts were startlingly similar to those of another “family annihilator,” John Emil List, who killed his family (wife, three children, and his mother) in New Jersey before disappearing. Following the 1971 murders, the bodies were discovered at least a month later, but List was long gone for nearly two decades. After List was featured on America’s Most Wanted, tips led to his 1989 arrest. A Reddit thread includes chatter of the similarities in both cases with one user pointing out that Xavier, like List, apparently removed family photos on his way toward total family annihilation.

Following Netflix’s dumping of additional evidence onto Reddit, users dug into newly-released footage that featured a statement from journalist Anne-Sophie Martin, who appears in the “House Of Terrors” episode. What Martin said supports this theory:

“In the United States there is a much-cited case that resembles the Ligonnes case in a fascinating and disturbing way … All this precise and exhaustive preparation from beginning to the end, they’re madly similar.”

Theory #3: Xavier Dupont de Ligonnèss’ Family Members Believe His Wife And Children May Still Be Alive

This is a truly wild one that not even the Reddit user in question (Hairyfeetfairy) fully believes, but it does give him pause. The user refers to a blog that was purportedly authored by Xavier’s family. They posted a timeline of events related to the case and make claims that include possibly botched autopsies and death certificates, and they point out how difficult it would be for Xavier to have moved “over 1 ton of soil… in an area where you could not stand up” to bury the bodies. Fair point?

It gets weirder. The family members claim that Xavier’s wife was sighted several times after her stated death date, and that she had contact with the children’s friends. Then there are these several claims of inconsistent events in the house after Xavier reportedly departed France:

“Apparently things seemed to be moved in the house after the supposed departure of Xavier. The family says police reports were inconsistent, talking about a tablecoth that would sometimes be there, sometimes not. Cleaning equipment being moved as well. They mention that on the day that the police found the bodies, there was a bucket and mop in the kitchen, and the mop was still wet. They also say that the slab of concrete on top of the bodies was still soft, which could indicate that it was laid much more recently than Xavier’s departure.”

Theory #4: Xavier Dupont de Ligonnèss Was Being Blackmailed Before Murdering His Family

Reddit user Jackp536 wonders whether Xavier owed a lot of money to a lot of people and that he was possibly also being extorted or blackmailed. Around the time of the murders, Xavier did withdraw money from the family’s accounts, but that seems like a standard move for someone who’s going on the run and doesn’t want to leave an electronic/credit-card trail. Still, it’s conceivable that he was involved in some shady transactions or even that he was being extorted for an unknown sum, like so:

“The hesitance to kill his oldest biological son, while the show draws the conclusion it could be about inheritance of his aristocratic title, could it also have been that he was being actively blackmailed/extorted? Like to me there’s something fishy about how he came home and at some point or another was given sleeping pills, but not once in that time was the son given reasonable evidence to leave … Furthermore, the money he withdrew. Yes it makes sense to not leave a trail with a credit card while on the run, so ofc he wanted to make sure he was only paying things with cash. However, is it possible that he was being extorted in some way or blackmailed?”

Theory #5: More Theories Are Yet To Come

This one seems like a no-brainer. Obviously, people will continue to keep churning out theories in an effort to help solve this family-annihilation case. One can only hope that one will lead to the killer(s).

Netflix’s ‘Unsolved Mysteries’ is currently streaming six episodes with more to come.