CRANS-MONTANA, Switzerland (AP) — Investigators said Friday that they believe sparkling candles atop Champagne bottles ignited a fatal fire at a Swiss ski resort when they came too close to the ceiling of a bar crowded with New Year’s Eve revelers.

Authorities planned to look into whether sound-dampening material on the ceiling conformed with regulations and whether the candles, which give off a stream of upward-shooting sparks, were permitted for use in the bar.

Forty people were killed and another 119 injured in the blaze early Thursday as it ripped through the busy Le Constellation bar at the ski resort of Crans-Montana, authorities said. It was one of the deadliest tragedies in Switzerland’s history.

Officials said they would also look at other safety measures on the premises, including fire extinguishers and escape routes. The attorney general for the Valais region warned of possible prosecutions if any criminal liability is found.

Arthur Brodard, 16, from the Swiss city of Lausanne, was among the missing. His mother, Laetitia, was in Crans-Montana on Friday and frantic to find him. She held out “a glimmer of hope” that he might be one of the six injured people who had yet to be identified.

“I’m looking everywhere. The body of my son is somewhere,” she told reporters. “I want to know, where is my child, and be by his side, wherever that may be — be it in the intensive care unit or the morgue.”

The injured included 71 people from Switzerland, 14 from France and 11 from Italy, along with citizens of Serbia, Bosnia-Herzegovina, Luxembourg, Belgium, Portugal and Poland, according to Frederic Gisler, police commander of the Valais region. The nationalities of 14 people were unclear.

Among the crowd was Axel Clavier, a 16-year-old from Paris, who said he felt as if he was suffocating inside the Swiss Alpine bar where moments before he had been ringing in the new year.

The teenager escaped the inferno by forcing a window open with a table. The dead included one of Clavier’s friends, and he told The Associated Press that two or three other friends were still missing hours after the disaster.

An impromptu memorial took shape near the bar, where mourners left candles and flowers. Hundreds of others prayed for the victims at the nearby Church of Montana-Station.

A French teenager on Friday brought a bouquet of tulips to the regional hospital in Sion for her best friend, a fellow 17-year-old girl who was badly burned and in intensive care. The two attend school together in Lausanne, said the girl, who was in distress and did not give her full name to the AP.

But when she arrived at the hospital, her friend had been heavily sedated for a dressing change and could not see visitors. It was the latest in hours of heartbreak for the teen, who had intended to join a dozen schoolmates at the bar but ultimately decided against it.

She said she has since learned that two of the 12 are in a Zurich hospital. She did not know if the others survived.

On Instagram, an account filled up with photos of people who were unaccounted for, and friends and relatives begged for tips about their whereabouts.