Investigators are racing to establish how and why the deadly New Year's Eve fire at a bar in a Swiss ski resort spread so rapidly.
Authorities on Friday said in a press conference that sparklers attached to champagne bottles that were held too close to the ceiling appear to have started the blaze in the basement of Le Constellation bar in Crans-Montana.
But how the fire took hold with such ferocity, killing at least 40 people and leaving 119 injured, many seriously, is now a key focus for officials - as is the bar's safety record.
BBC Verify has been examining videos taken by survivors and onlookers and speaking to fire safety experts to find clues about what went wrong.
Bottles with sparklers held in the air
Two striking images shared widely online show people carrying champagne bottles with lit sparklers above their heads, with a crowd around them. One image shows flames starting to gather on the ceiling above people holding five of these bottles aloft.
Questions about foam padding on ceiling
Another focus is on foam-like padding on the bar's ceiling and whether it was compliant with safety standards. Fire safety experts noted the materials visible in photos suggest that untreated polyurethane foam is highly flammable, which could have contributed to the rapid spread of the fire.
Exit routes from the bar
Authorities say they will also focus on exit routes at the bar, which sits across two levels. Videos filmed as the fire took hold show people trying to extinguish the flames before trying to escape up narrow stairs, which can create fatal bottlenecks in emergencies.
Officials confirmed there was more than one exit from the building at the time of the fire but have not yet determined whether all were accessible.
Sparklers used before
Investigators are analyzing footage showing that sparklers attached to bottles have been used in the bar since at least 2024, raising further questions about the establishment's safety practices.


















