(CNN) -- A French prosecutor investigating a ski accident in which former world champion racing driver Michael Schumacher was seriously injured said Wednesday that speed was not an important factor.
Schumacher has been in a medically induced coma for the past 10 days and has undergone two surgeries since the December 29 accident. His doctors say he is in stable but critical condition.
Prosecutor Patrick Quincy, speaking at a news conference in Albertville, said the investigation had made progress but could still take several weeks to complete.
"Speed is not a particularly important element for us in that inquiry," he said.
Police investigator Stephane Bozon said it was not possible to estimate Schumacher's speed in terms of kilometers per hour, "but this was the speed of a very good skier on a slope which was not very steep."
Another investigator, Benoit Vinneman, said Schumacher was traveling at "a normal speed for an experienced skier."
Quincy ruled out problems with Schumacher's skis, which he said were almost new. The piste, or ski run, also appeared to be correctly marked according to French standards, he said.
Schumacher hit a rock hidden beneath the snow while skiing in an area between two marked pistes, the prosecutor said, which catapulted him face first onto another rock. Schumacher ended up 9 meters (30 feet) from the edge of the piste, he said.
Investigators have begun studying footage filmed on a small camera attached to Schumacher's helmet, but further analysis is needed, Quincy said.
The video is only two minutes long and has a very limited field of vision, he said.
He said experts may be able to use it to determine Schumacher's precise position in relation to the edge of the piste and possibly the speed at which he was traveling at the time of the accident.
Investigators are talking to family members, witnesses and others in connection with the Schumacher inquiry, he said.
The investigation is no different from those carried out in other serious accidents on the slopes, Quincy added. There are about 50 such a year in the Albertville area, he said.
Schumacher is a formidable figure in Formula One, and his plight has attracted global interest and an outpouring of support from the sport's fans.
However, his family wants the media to keep its distance and appealed Tuesday for privacy.
"Please support us in our common fight with Michael," Corinna Schumacher, the wife of the race car driver, said in a statement. "It is important to me that you (media) relieve the doctors and the hospital so that they can work in peace. I kindly ask you to trust their statements and leave the clinic. Please also let our family in peace."
Schumacher is the most successful driver in Formula One history, driving for the Benetton and Ferrari teams and claiming a record seven world titles and 91 grand prix wins.