New footage shows a fresh angle of the moment a packed Swiss nightclub burst into flames after a waitress lifted sparklers towards a low ceiling.
The video lays bare just how quickly the blaze took hold, and hints at why dozens of revellers did not immediately realise the danger above their heads.
Partygoers can be seen dancing and cheering as a waitress wearing a helmet is carried on a man's shoulders through the club, holding champagne topped with lit sparklers.
As she raises the sparklers, the ceiling appears to catch almost instantly, flames licking across the surface.
But instead of stopping, the waitress continues through the venue as part of the celebration, and the crowd turns to follow her, their backs to the fire as it spreads overhead.
The inferno killed 41 people and injured 115 others at Le Constellation in the ski resort of Crans-Montana on January 1.
Witnesses described seeing people burning and suffocating to death as they raced to escape the 'horror movie'.
Panicked partygoers rush towards the exit as smoke fills the basement venue, while others continue filming as flames spread overhead.
Dramatic new footage reveals the moment a packed Swiss nightclub burst into flames after a waitress hoisted champagne bottles topped with sparklers beneath a low ceiling
The video lays bare just how quickly the blaze took hold, and hints at why dozens of revellers did not immediately realise the danger above their heads
Partygoers can be seen dancing and cheering as a waitress wearing a helmet is carried on a man's shoulders through the club, holding champagne topped with lit sparklers
Crowds of people can be seen piling out of the door as they run for their lives while others scream to find their friends amid the chaos.
Swiss prosecutors have launched an investigation into the club's owners, Jacques and Jessica Moretti.
Earlier this month, furious parents publicly attacked the Morettis, blaming them for their children's deaths.
As Jacques and Jessica arrived at the prosecutor's office in Sion for their fourth day of questioning, dozens of grieving relatives swarmed around the building's entrance, wearing clothing bearing images of their deceased loved ones.
The pair, who have pinned the blame on a waitress who also died in the fire, are under judicial supervision following the inferno.
As they made their way into the building to testify last Thursday, several relatives rushed towards the pair, who were flanked by just a police officer and their lawyer.
'It was a real mob. The Morettis... had hardly any protection when the relatives' anger erupted.
'Everyone rushed at the innkeepers, who were pushed against the building's wall and couldn't get away,' a reporter at the scene told 20 Minuten.
The inferno killed 41 people and injured 115 others at Le Constellation in the ski resort of Crans-Montana on January 1
Angry relatives hurled insults as the pair cowered behind their lawyer, with one sobbing parent heard yelling: 'You killed my son, you killed 40 people, you will pay for this'.
Ms Moretti, 40, appeared close to tears as she waded through the mob, while the brother of a 17-year-old victim named Trystan allegedly attempted to kick her after repeatedly asking her to look him in the eye.
Trystan's mother, Vinciane Stucky, who was also present, told local media: 'We will neither forgive nor forget.'
'I'm here for Trystan,' said his father, Christian Podoux. 'I want Jessica Moretti to know how hard she has hit fathers, mothers, brothers, and sisters.
'She distanced herself, left the Constellation. Others, the young people, helped so much, and she just left. That's not right.'
The teenage victim's younger siblings, Tobyas, 14, and Yaelle, 15, were also present alongside their parents as they joined the raging crowd upon the Morettis' arrival.
'We want Jessica Moretti to apologise,' they told local reporters. 'I'm Trystan's little brother, and I came here to show Jessica Moretti that she has destroyed families, to look us in the eye.'
Tobyas added: 'What happened isn't normal. We want justice. Moretti is undoubtedly guilty, as are the municipality of Crans-Montana and the canton of Valais.'
After repeatedly being called 'murderers' by the furious group, Mr Moretti faced the crowd and said: 'If we have to pay, we will pay. We are not the Mafia; we are workers. We will take responsibility, we will get to the bottom of this, we promise you, we are here to achieve justice.'
The hearing in Sion touched on staff training at the nightclub. According to Ansa news agency, Ms Moretti admitted that her staff had not been trained for fire emergencies.
'There were never any evacuation drills because nobody asked us to,' Moretti reportedly said.
She also spoke about the families impacted by the fire: 'We knew that the families wanted to meet with us today. We understand your anger, your hatred.
'I reaffirm that we are available for any questions and will be there for you,' Ms Moretti said through tears.
Regarding her role during the night of the fire, Moretti said: 'My priority was to raise the alarm, evacuate people, and call the fire department as quickly as possible. I'm the daughter of a firefighter myself, and that's my reflex.'
The French couple have firmly blamed their young staff for causing the inferno and blocking an escape exit, with leaked interview records pointing to them saying: 'It's not us, it's the others'.
Prosecutors were told the sparklers display was 'Cyane's show', according to interview records.
'I didn't forbid her from doing that,' he told prosecutors, adding: 'I didn't make her pay attention to safety instructions. We didn't see the danger. Cyane liked doing that – it was a show, she liked to be part of the show.'
She previously claimed: 'Cyane liked to deliver these bottles – she did it of her own accord.
'If I had thought there was the slightest risk, I would have forbidden it. In ten years of running the business, I never thought there could be any danger.'
The French couple is under criminal investigation, facing charges of manslaughter by negligence, bodily harm by negligence, and arson by negligence.
They face up to 20 years in prison if charged and found guilty of manslaughter.
