A judge in Switzerland has ordered that one of the two co-owners of the ski resort bar where 40 people died in a fire on New Year's Eve be kept in detention for 90 days.

Swiss prosecutors have argued that Jacques Moretti, a French national, is a potential flight risk. He and his wife Jessica, who is also French, are suspected of manslaughter by negligence, bodily harm by negligence, and arson by negligence.

The blaze at Le Constellation bar in Crans-Montana also left 116 people injured. Many of the victims were aged under 20.

The fire is believed to have been started by sparklers in champagne bottles raised too close to the ceiling during celebrations.

Authorities acknowledged last week that the bar in the popular ski resort had not undergone safety checks for five years.

Jacques Moretti was first detained on Friday for an initial period of 48 hours. On Monday, a judge ruled that he should remain in custody for three months, a provisional measure that can be renewed under Swiss law. This detention may be lifted upon payment of bail, the amount of which will be decided later.

The couple were placed under criminal investigation days after the devastating fire. Jessica Moretti, under house arrest, expressed sorrow about the unthinkable tragedy. Prosecutors believe that the fire started when revelers celebrating the New Year raised champagne bottles with sparklers, igniting sound-insulating foam on the ceiling of the basement bar.

Local authorities are under scrutiny following revelations that the bar had not been inspected for five years, contradicting requirements for annual checks. Mayor Nicolas Feraud has stated that they accept responsibility for this oversight, promising that sparklers will be banned in local venues.

The tragedy has deeply impacted the community, especially since the majority of the victims were young, with eight under the age of 16. The injured individuals include many sustaining severe burns, with eighty still hospitalized in various medical facilities across Switzerland and Europe.