Rescue workers have found the bodies of three climbers buried in an avalanche of ice and snow near a summit of Mont Blanc, sparking an investigation after they were only alerted to the missing trio 36 hours after the accident.
French interior minister Bernard Cazeneuve announced the investigation into the circumstances of the incident, which happened early on Tuesday.
The bodies of two women, a 32-year-old Slovakian and a 33-year-old dual Polish-Briton, were discovered on Wednesday night.
The body of the 50-year-old German guide was recovered early on Thursday, said Lieutenant Colonel Stephane Bozon, who heads the mountain rescue team in the French town of Chamonix.
The three were climbing Mont Maudit, a summit of Mont Blanc, 4,100 metres (13,450ft) high before dawn on Tuesday when a tower of ice swept over them and they fell 150 metres (500ft) to their deaths.
Rescue workers had to use chainsaws and a backhoe to free them from the ice, Lt Col Bozon said.
Blocks of ice had fractured as the team climbed, creating an avalanche of ice and snow, he said.Sixteen police officers, two dogs and a helicopter were mobilised to find the victims and recover their bodies, a statement by the interior minister said.
Lt Col Bozon said his team was alerted only on Wednesday evening to the missing climbers.
Two other groups of climbers in the zone had said that no-one was buried by the avalanche.
A New Zealand guide was killed in the same sector by an avalanche of snow on June 20.
Mr Cazeneuve said there have been eight fatal mountain accidents in France since last Saturday.