The blaze, likely from sparklers igniting foam, killed 41 and injured 116, mostly teenagers.
An 18-year-old injured in the deadly New Year's Eve fire at Le Constellation bar in the Swiss alpine resort of Crans-Montana has died, raising the death toll to 41.
The blaze had broken out in the early hours of Thursday, 1 January, in the basement of the crowded bar during celebrations.
Prosecutors believe sparklers on champagne bottles ignited soundproof foam on the ceiling.
Most victims were young, including teenagers from the age of 14, with 116 others injured, many suffering severe burns.
Victims included Swiss, French, Italian and other nationalities; some were airlifted to hospitals across Europe.
The main exit door opened inward, against fire safety rules, and the bar had had no recent inspections
One co-owner remains in custody as investigations into possible negligence continue.