UNSOLVED MYSTERIES is Netflix's remake of the eponymous show from the late eighties, which many in the US still consider the scariest show ever. Whereas the original show dealt only with US cases, Netflix's remake also explores cases from Europe, particularly France, where a case that might interest Croats happened.

It is a truly horrific case of the massacre of the Dupont de Ligonnès family in 2011 in Nantes, France.

In April 2011, the whole family that was loved and highly esteemed in their neighborhood just disappeared. Their belongings disappeared from the house, the windows were closed, and spouses Xavier and Agnes and their children Arthur, Thomas, Anne, and Benoit were nowhere to be seen.

One of their neighbors found that very strange, so she called the police. During the first few visits to the house, the police did not notice anything unusual. It looked as if the family had voluntarily left the family home. There were no traces of blood or any suspicious evidence until one day identical letters with a very suspicious story arrived at the addresses of family members and friends.

Xavier sent everyone a letter claiming that he was, in fact, an undercover agent working on drug cases for the US Secret Service and that he had to go to a witness protection program with his family. Many people immediately thought the story was suspicious, so they called the police once again to check the house.

During one of the visits, the police discovered something terrible. The bodies of the mother and her four children were found buried under the terrace. The mother and three children were buried in one place, while Xavier Dupont's eldest biological son, Thomas, was buried separately. Only the father was missing.

This horrible story quickly began to unravel. The investigation revealed that Agnes, Arthur, Anne, and Benoit were killed between April 3 and 5, 2011, and that Xavier, the prime suspect, stayed in the house for another week after the murder.

A day or two after murdering his family members, he called his son Thomas, who was in college, telling him to return home immediately because his mother was in the hospital. The police and the people close to the case believe Thomas spent a day or two with his father in the house before Xavier killed him and buried him separately from other family members.

French media wrote at the time that the father and son were seen having dinner together on April 4, and it appears that Thomas was killed in his own home afterwards. Xavier then left the city and was last seen in Roquebrune-sur-Argens, where he was filmed leaving the hotel, taking stuff from his car, and walking towards the mountains.

Looking at the footage from security cameras, it appears Xavier wanted to be spotted. That was the last time he was seen. While some claim that he committed suicide and that his trip to Roquebrune-sur-Argens was a "pilgrimage" of sorts, as he used to go there with his family on vacation, others think that he carefully planned everything and that he is hiding somewhere to this day.

"He could have taken a train and gone to Croatia and then further east," says one of the family's acquaintances in the documentary.

There are also some theories speculating that Xavier is currently hiding in South America. In 2015, a message arrived at the Agence France-Presse stating "I'm still alive... To this day," with Xavier's name in the signature.

Police have received more than 1,000 reports that Xavier had been seen in various parts of the world, but they have not been able to prove that it was really him.

Many hope that Netflix's new series will help solve this case, as since it was broadcast, many viewers have reported new information on the cases that were shown in the series.