"The helmet completely broke. It was in at least two parts. Ensa analysed the piece of the helmet to check the material, and all was okay," said a source close to the investigation.
"But why did it explode on impact? Here the camera comes into question. The laboratory has been testing to see if the camera weakened the structure."
Patrick Quincy, the prosecutor in charge of the investigation into the accident, will make an announcement today.
He is expected to clear the ski resort of any involvement and conclude that the manufacturers of Schumacher's ski equipment were not liable.
Schumacher remains in intensive care as doctors try to ease him out of an artificially induced coma. He had been skiing on the piste with his son and family friends. But shortly after 11am he "deliberately" skied on an off-piste stretch located in between two runs "with a number of dangers, notable rocks", according to investigators.
It was here, no more than 6m from the piste, that he struck a partially covered rock and then catapulted on to another, crashing his head with such force that his helmet split in two.
Lawyers had argued that managers of the ski resort might face up to three years in prison because the dangers lurking within the off-piste section were not properly marked.
The resort, in response, hired a top lawyer, Maurice Bodecher, who is a specialist in ski and criminal law and was until 2010 the head lawyer for the French Ski Federation.
But, presenting initial findings 10 days into the investigation, the police chief Stephane Bozon said: "The piste markers conformed to the regulations. Unfortunately, this off-piste area had a number of dangers, notably the rocks being only barely visible, covered with five to 10cm of snow."
Mr Quincy, a former policeman who has been the prosecutor at Albertville since 2009, added that all safety procedures by mountain authorities "had been respected".
Meanwhile, the seven-time Formula 1 world champion is receiving round-the-clock care in Grenoble University Hospital.
His wife, Corinna, 44, with whom he has two children, Gina Marie, 16, and Mick, 14, has remained at his bedside.
His family have said he was "still in a waking-up process", and that only time would tell whether he made a full recovery. They said the most important factor was not the speed of his recovery, but that it progressed in a "continuous and controlled way"and they "strongly believe" he will recover.
Schumacher is fed through a tube to his stomach and gets oxygen via a hose from a machine next to his bed as he still cannot breathe independently.
Fight for life
*Investigators suspect that Schumacher's helmet camera could have worsened the blow, causing the helmet to shatter into pieces.
*The camera was undamaged.
*He remains in intensive care as doctors try to ease him out of an artificially induced coma.
