Since January 15, 2026, four young people — Thomas Allart (20 years old), Margot Nizan (16 years old), Léa Duguet Vermandel (16 years old) and Clément Dumont (16 years old) — have not been heard from. The Laon public prosecutor’s office has opened an inquiry for a missing person concern and the Sissonne gendarmerie has issued a call for witnesses. Investigators believe they may be traveling together in a white Peugeot 206, license plate AY-354-TJ. Reports mentioned in recent days remain, at this stage, to be confirmed.
Young Missing: A Disappearance of Four, Between Aisne and Val-d’Oise
They are different ages, live in different places, and yet the same absence weighs on the same hours. Three minors and one young adult. Three teenagers still have many appointments and plans. Additionally, a 20-year-old young man is supposed to be free.
The departures were noted in Aisne and Val-d’Oise. The case quickly took on a collective dimension: this is not an isolated disappearance, but a group. When families find that messages get no reply, concern grows. Furthermore, unanswered calls amplify that concern. It becomes an emergency.
It was this shift that led the Laon public prosecutor’s office to open an inquiry for a missing person concern. This classification under French law allows for a broader mobilization of investigative resources. Indeed, the lack of news raises fears of danger, especially when minors are involved.
Gendarmerie Investigation: What Is Known About the Last Hours
At this stage, the timeline is made of precise reference points, but it leaves a large shadowed space between them.
According to information provided as part of the call for witnesses, Thomas Allart was last seen in Cuissy-et-Geny on January 15 at 8:25 a.m. Clément Dumont was reportedly seen in Athies-sous-Laon the same day, also at 8:25 a.m.
For Léa Duguet Vermandel, the last known element places her at her home in Lappion on January 15 at 10:30 p.m. Finally, Margot Nizan was declared missing from her home in Argenteuil during the night of January 15 to 16.
One detail ties the pieces together in this puzzle: the four young people could be traveling “together” in a white Peugeot 206 with plate AY-354-TJ. The gendarmerie specifies that the vehicle would have been driven by the only adult in the group.
Minors Running Away? One Lead, Without Ruling Out Others
In the first days after a disappearance, hypotheses sometimes follow each other too quickly. Investigators, however, proceed by cross-checking, not by intuition.
The coordinated runaway lead is mentioned. It is neither a verdict nor a certainty. It is a working hypothesis based on what is observed. Indeed, there are closely timed departures, a group, a vehicle and silence.
Unconfirmed reports have circulated, mentioning possible sightings in various areas. Notably toward Charleville-Mézières, Reims or even Luxembourg. Law enforcement generally recalls, in this type of situation, that “leads” must be verified. Indeed, these leads come from private messages or social networks and require validation before being taken into account.
Caution is not cold. It protects. It prevents a rumor from becoming a false certainty. Moreover, it stops an erroneous detail from steering the search in the wrong direction. Finally, it prevents someone from being unfairly implicated.
“Missing Person Concern”: What That Changes in the Investigation
In France, when a person disappears, the judicial response depends on the circumstances. An absence can be a simple “disappearance,” often handled by checks. However, it can also be a missing person concern when the context raises fears of endangerment.
In this case, the framework is clear: minors are involved. Additionally, according to the call for witnesses, there has been no contact with the families for several days. That is enough to justify a more structured investigation.
Concretely, investigators can increase interviews and exploit available technical elements. They can also check possible routes, cross-check testimonies, and process received information more quickly. The goal is simple: locate the group as quickly as possible and determine what happened.
This classification does not imply that a crime has been established. It only states: the absence is worrying, and the state is allocating more resources to understand and find them.
When the Investigation Crosses the Border: The Role of the Tournai CCPD
Aisne is not strictly a border department. However, its roadways quickly open toward the Ardennes and Belgium. They also lead further toward Luxembourg. As soon as a cross-border lead is considered, investigations can rely on cooperative mechanisms.
That is where the French-Belgian Police and Customs Cooperation Center (CCPD) in Tournai comes in. This mechanism serves to accelerate the exchange of information between French and Belgian services: license plates, reports, road checks, operational information.
In practice, this cooperation aims to reduce the “loss of time” between two administrations. Indeed, this is necessary when an investigation does not stop at a line on a map. It allows opening fast channels: verifying a report, confirming or refuting a location, cross-checking information from the field.
If the Luxembourg lead is mentioned, other relays exist at the European level. But at this stage, the authorities have not publicly detailed the results of these checks. Nor have they specified priority search areas.
Families, On The Edge Of The Phone
In disappearance cases, the investigation advances with procedures; relatives move forward with lack. Families live through a succession of interminable minutes, punctuated by jolts: a notification, a call, a white car passing that makes the heart race too fast.
Silence is the heaviest thing. A teenager can go away; a young adult can too. However, the absence of a sign, a message or a “I’m fine” changes the situation. Indeed, it leads to a place where imagination activates and anxiety becomes physical.
Relatives often try to help. They share the call for witnesses, question friends, retrace possible routes. They hope that a detail, even tiny, will turn the case toward clarity. In this specific case, the idea that the four young people are together can also feed another hope: that they protect each other, that they help one another, that none of them is alone.
How To Help Without Fueling Rumors
A call for witnesses has a specific goal: obtain useful and verifiable information. In an era where everything is shared in seconds, the most effective help is often the simplest.
- If you believe you have seen the young people or the vehicle, note the place, the time and the direction. Also, record any concrete element without interpretation.
- Avoid posting unverified information online: a “someone told me” can divert attention or even expose minors.
- Do not share additional personal details (addresses, schools, private numbers). Public dissemination should remain under the control of authorities.
Anyone with information is invited to contact the gendarmerie. For the Sissonne brigade, the contact number is 03 23 80 07 17. In an emergency, dial 17. For cases involving a minor, 116 000 is also a listening and support number dedicated to child disappearances.
What Is Expected Now
As of January 21, 2026, the families have not been publicly informed of a confirmed location of the missing persons. The investigation continues, fueled by testimonies and verifications.
In this type of case, the first hours are crucial. However, the following days also matter. Indeed, a vehicle can be seen later. An purchase can leave a trace. A camera can illuminate a route. Finally, a witness can remember afterward.
The disappearance of Thomas Allart, Margot Nizan, Léa Duguet Vermandel and Clément Dumont puts the authorities in a race: find them before time increases the risk. For relatives, the wait is of another nature: it hinges on one sentence, the shortest and most hoped-for — “they have been found.”
Meanwhile, investigators’ message remains unchanged: any information can be valuable. However, it must be transmitted to the right place. Additionally, it must be done with the necessary rigor. That way, worries do not turn into noise.