Officials on Saturday said they recovered the bodies of the nine backcountry skiers killed earlier this week after an avalanche struck the California side of Lake Tahoe.

Among those who died were six close friends who were “passionate, skilled skiers” and three professional guides.

Family members previously identified Carrie Atkin, Liz Clabaugh, Danielle Keatley, Kate Morse, Caroline Sekar and Kate Vitt as victims of the slide.

The Nevada County Sheriff’s Office also confirmed the identifies of three employees of Blackbird Mountain Guides who were killed in the avalanche: Michael Henry, 30, Andrew Alissandratos, 34, and Nicole Choo, 42.

“We are grateful that we can bring them home,” said Shannan Moon, the sheriff of Nevada County, California.

Authorities had to wait to recover the bodies because avalanche conditions remained unsafe for rescuers to spend prolonged time at the site of the slide. Helicopters from the utility company Pacific Gas & Electric dumped buckets of water on the slope near the site of the slide, with the goal of prevent snow from cascading down the slope toward rescuers.

Five of the bodies were recovered on Friday and hoisted out by helicopters. The remaining four were brought out on Saturday.

A total of 15 skiers were involved in the avalanche incident. Six survived the incident. Two suffered non-life-threatening injuries in the slide.

Brutal weather and the threat of more avalanches had kept crews from safely recovering the nine people killed for several days.

Several investigations into the avalanche incident are being conducted by several agencies. The Sierra Avalanche Center will write an incident report about the avalanche, the California Division of Occupational Safety and Health (Cal/OSHA) is conducting an investigation of potential workplace safety violations and the sheriff’s office is also pursuing an investigation.

“We are investigating the incident to determine if there were any factors that would be considered criminal negligence,” said Ashley Quadros, a sheriff’s office spokesperson in an email.

The sheriff’s office said it was still gathering information from survivors about what happened on Tuesday.

“We’re still getting a lot of the more formal interviews,” Moon said, adding that the investigation would be lengthy before the group’s decision-making process was clear. “Clearly, the families have questions as well.”

Many questions remain, including how the group assessed the weather and avalanche conditions, how it selected a route, whether the avalanche was triggered naturally or by a skier and how social pressures shaped decision-making.

Moon said the skiers did hasten their departure from the Frog Lake Backcountry huts, as the storm on Tuesday intensified.

“The information we have at this time is that this was the last day of their three day tour, and they did decide to leave early to try to get off the mountain early,” Moon said.

Blackbird Mountain Guides did not immediately respond to a request for comment Saturday.