Switzerland held a national day of mourning on Friday for the 40 people who died in an Alpine bar fire during a New Year’s Eve celebration, as prosecutors requested one of the managers to be placed in pre-trial detention.

Valais region’s chief prosecutor Beatrice Pilloud said in a statement the detention of the man was needed to avoid a “risk of flight.” The man’s wife and co-manager will remain free under judicial supervision, the statement said.

A Swiss business register lists French couple Jacques and Jessica Moretti as the owners of Le Constellation bar, in the Alpine resort of Crans-Montana, where a fire broke out less than two hours after midnight on Jan. 1. As well as the fatalities, 116 people were injured, many of them seriously.

Swiss authorities have opened a criminal investigation into the owners, who are suspected of involuntary homicide, involuntary bodily harm and involuntarily causing a fire.

A memorial service and a minute’s silence marked Friday’s national homage, while church bells across Switzerland rang out for five minutes, beginning at 2 p.m..

Investigators have said they believe sparkling candles atop Champagne bottles ignited the fire when they came too close to the ceiling. Authorities are looking into whether soundproofing material on the ceiling conformed with regulations and whether the candles were permitted for use in the bar. Fire safety inspections hadn’t been carried out since 2019.

The severity of burns made it difficult to identify some victims, requiring families to supply authorities with DNA samples. Police have said many of the victims were in their teens to mid-20s.

An autopsy has been ordered for five of the six Italian victims and has been delegated to the prosecutors’ offices in Milan, Bologna, and Genoa, where the bodies of the victims have been returned.

“What happened is not a disaster: It’s the result of too many people who didn’t do their job or who thought they were making easy money,” Italian Premier Giorgia Meloni said during a press conference on Friday. “Those responsible must be identified and prosecuted.”

Meloni said the State Attorney General’s Office has contacted the Swiss Attorney General to follow the investigation. She also confirmed that the Rome Prosecutor’s Office has started a separate probe.

“The families have my word that they will not be left alone while they seek justice,” she added.

The Paris prosecutor’s office Monday announced that it was opening a probe to assist the Swiss investigation and make it easier for families of French victims to communicate with Swiss investigators. Nine French citizens were killed, the youngest of them aged 14, and 23 others were injured.