Police said they worked with the Institute of Forensic Medicine and the country’s disaster victim identification protocol to return the victims to their loved ones.

All the victims, including numerous teenagers, have been positively identified in the deadly inferno that erupted at a New Year’s party in Switzerland last week.

Valais canton police finished identifying 40 people who died at Le Constellation bar in the Swiss Alps on Thursday night. Police said Sunday they worked with the Institute of Forensic Medicine and the country’s disaster victim identification protocol to return the victims to their loved ones.

Officials offered the nationalities and ages of the victims who were identified Sunday, but only some were also referred to by their sexes. Police provided no names.

The victims included several teenagers who were as young as 14 and came from multiple countries. Six Swiss teenage girls ages 14 to 18 were identified Sunday.

A 15-year-old who held citizenship from France, Israel and the United Kingdom was among those who died. Police identified six French more citizens, the youngest of whom was 14 and the oldest of whom was 39. A 17-year-old Belgian girl was also among those killed.

Four 16-year-olds and a 15-year-old from Italy, as well as an Italian-Emirati who was 16, were positively identified Sunday.

“Out of respect for the relatives, no further information will be provided at this time,” police said Sunday.

The deadly blaze in the town of Crans-Montana appears to have been caused by sparklers on top of Champagne bottles at the bar. Authorities believe the sparklers were too close to the ceiling, which had a soundproof lining that ignited.

Ebenezer Mehari, 17, told NBC News that he lost four of his friends in the fire. He was blinded by the thick smoke that enveloped the club but was pulled to safety by a stranger.

Mehari, who has lived in the area for 15 years, described the scene as “hell.”

“Somebody was dying in front of me, and I couldn’t do anything,” he said. “Her face was so burned it was red.”

An investigation has been opened into the managers of the bar, who are suspected of negligent homicide, negligent bodily harm and causing fire by negligence, police said. Officials plan to look into what safety measures were in place at the time of the fire, as well as whether soundproofing material on the ceiling that is believed to have caught fire conformed with regulations.

Swiss President Guy Parmelin shared his “deepest condolences.”

“Behind these numbers are faces, names, families, destinies brutally interrupted,” Parmelin said at a news conference Thursday.