A day after a New Year’s celebration at a ski resort in the Swiss Alps left at least 40 people dead and more than 100 injured, investigators said on Friday they believe sparklers attached to champagne bottles were to blame.

The blaze broke out at Le Constellation bar in Crans-Montana, Switzerland, just after midnight early Thursday morning, authorities said. Photos from the scene show revelers holding what appear to be sparklers attached to champagne bottles and a small fire starting on the ceiling.

Speaking at a press conference on Friday, Beatrice Pilloud, the attorney general of the Valais canton, where the fire took place, provided more details about how authorities think the fire started.

What we know about how the fire began

Pilloud told reporters that “some hypotheses” about the blaze “can be confirmed.”

“As things stand, everything points to the fire starting from sparklers or flares placed in champagne bottles that came too close to the ceiling, which very rapidly led to a flashover fire,” Pilloud said.

Authorities are investigating whether soundproofing material that lined the ceiling and walls of the venue was up to code, and whether sparklers were permitted to be used inside the bar.

When asked about the sparklers and how partygoers would have gotten them, Pilloud said anyone could have purchased the “birthday candles” and did not require authorization to do so.

There was a fireworks ban in Crans-Montana at the time of the blaze due to a lack of rainfall in the area, officials said.

Tracking the death toll and injuries of the blaze

As of Friday, at least 40 people were confirmed dead and at least 119 others were injured, officials said. Investigators are continuing to work to find and identify the victims.

“These figures are shocking,” Mathias Reynard, the president of the Valais canton, said at the press conference on Friday. “We are acutely aware of the unbearable weight of every passing minute without answers.”

Of those injured, 71 Swiss nationals, 14 French nationals and 11 Italian nationals were recorded. Four Serbians, one Bosnian national, one Belgian national, one Luxembourgian national, one Polish national and one Portuguese national were also among those injured. A further 14 of the patients being treated have not yet had their nationality confirmed, Valais Cantonal police commander Frédéric Gisler said. Le Constellation, the venue where the fire occurred, reportedly draws a younger crowd, and many of the victims were in their teens to mid-20s.

On Thursday, Swiss President Guy Parmelin described the deadly fire as “one of the worst tragedies that our country has experienced.”

The status of the ongoing investigation

"At no moment is there a question of any kind of attack," Pilloud said Friday.

"For the time being, we don't have any suspects," she added when asked if anyone had been arrested over the fire. "An investigation has been opened, not against anyone, but to better understand the circumstances of this dramatic fire."

The number of people in the bar at the time of the fire is "unknown," according to Pilloud, but whether the number of partygoers who attended the celebration exceeded the venue’s maximum capacity will be part of the investigation. “We are talking about more than 30 specialists striving to provide clarity to families — to let them know if their loved one or child has passed away or been victimized,” she said. “There is a clear methodology in place.”