Camera on Schumacher's ski helmet inspected

A source said it had been taken to see if it can yield any clues as to the circumstances of the accident

A camera fixed to the ski helmet of Michael Schumacher is being inspected by investigators probing the accident that has left the German retired racing legend comatose in a French hospital with critical head injuries.

A source close to French authorities handling the investigation disclosed the existence of the camera late Friday.

The source said it had been taken to see if it can yield any clues as to the circumstances of the accident.

Schumacher's 14-year-old son Mick, who was skiing with his father at the time, was also being questioned by investigators, the source said, confirming information reported by the French newspaper Dauphine Libere.

The developments in the probe came the day Schumacher turned 45 while still in an induced coma in a hospital in the French Alpine city of Grenoble after his December 29 accident.

Fans marked the birthday with a silent vigil outside the facility, part of which was organised by Ferrari, Schumacher's former team.

French authorities are examining various factors in the ski accident, in which Schumacher's head hit a rock so hard his helmet was split in two.

Although he was conscious when airlifted from the unmarked run in the Meribel resort, where he owns a property, Schumacher was agitated and soon fell into a coma, prompting his transfer to Grenoble hospital.

He has undergone two operations to remove blood and pressure from his brain. His manager said in the last update on Wednesday that he remains in a critical but stable condition.

His family is at his bedside, including his wife Corinna, his two teenage children, his father Rolf and brother Ralph, who is also a racing driver.