In the snow-dusted street outside St Christopher’s Church, hundreds joined a special Sunday Mass for the victims of the fire that tore through Le Constellation bar on New Year’s Eve.

Many hugged each other, crying quietly, as they remembered the dozens killed and those still in hospital with severe burns, fighting for their lives.

During the service, several in the crowd fainted and fell to the ground, overcome.

Police say more than 20 of the dead have now been identified, although not named publicly. Their bodies are being returned to their families, some of whom who had been holding on to the hope their children might yet be found – injured, but alive.

They’re now receiving the worst possible news.

Ever since the fire, Laetitia Brodard had been posting pictures of her teenage son Arthur online and appealing for help to find him. On Sunday, she was at the memorial service, being comforted by friends.

“He died that first day,” Laetitia confirmed to me.

In an emotional statement on Facebook, she said that Arthur had “gone to party in paradise”.

The victims’ bodies were so badly burned by the fire they are difficult to identify. Even some of those injured and in hospitals haven’t been named yet – they remain unconscious and unrecognisable.

For the dead, forensics experts are having to use DNA samples and dental records, and for the families the wait is agonising.

The bar was packed full of young people that night, many of them just teenagers. The drinking age in Switzerland is 16.

Some of the survivors joined a silent procession after the Sunday Mass from the church towards the bar itself. Above, in the stunningly beautiful Swiss Alps, cable cars went on sliding up the mountain carrying tourists to ski.

The site of the fire is still screened off behind white plastic sheets, but in front of it are heaps of flowers and soft toys at a shrine that keeps growing.

Among the bouquets, there are handwritten notes with names and photographs.

At one point, the crowd burst into applause: a large group of firefighters and rescue workers in uniform had reached the memorial and stood arm in arm, sobbing for those they couldn’t save.

For the people of Crans, they are heroes.

The local fire commander – who considered leaving his job after what he experienced here – told us he and his colleagues were now a giant family.

“I need them, and they need me,” David Vocat said, very tearful. “All my thoughts are for the victims and their families. I am so sorry.”

We’ve spoken to teenagers who saw people running from the burning bar and describe horrific scenes they say they can never forget.

A criminal investigation has now been opened. The bar owners, a French couple, are suspected of killing and causing arson and bodily harm through negligence.

Police and prosecutors have been examining images filmed inside Le Constellation that show the moment the fire started, with bar staff carried on others’ shoulders, delivering champagne bottles with sparklers attached.

The sparks appear to set fire to the ceiling, which was covered with foam for soundproofing, and the flames spread very quickly.

Investigators will examine whether the foam and other materials met safety standards.

They will look into possible overcrowding, access to emergency exits from the basement and whether there were fire extinguishers.

Some videos show teenagers trying, hopelessly, to put the fire out with their T-shirts. Initially, many didn’t realise the immense danger and went on dancing and even filming the fire, instead of fleeing.

On Sunday, a group of men – some with their faces covered in black scarves – formed a semi-circle to remember one man killed at the bar which locals call “Stefi”.

“We’re here for our colleague,” one of them said, struggling to speak. “Stefi was his final path. May he now rest in peace.”

“It was important to be here, with the families. We can’t change things, we can only be here,” Diana said, after praying hand-in-hand with two other women for a group of friends who are still in hospital.

“We only hope they make it.”

“We are not angry,” Diana told me. “But we believe the police will do their work well and we hope there is justice.”