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.