Prosecutors expand Swiss ski bar fatal fire probe to include mayor, documents show

A building with flame coming out of it.

Mobile phone vision shows Le Constellation bar engulfed by flames in the early hours of January 1. (Supplied)

In short:

Swiss prosecutors have added the mayor to those under criminal investigation for a fatal New Years Eve ski resort fire that killed 41 people.

The fire that tore through the "Le Constellation" bar in Crans-Montana was one of the worst disasters in modern Swiss history.

What's next?

The case now has nine defendants who, if convicted, could face a maximum penalty of four and a half years in prison.