A prosecutor in Grenoble, France announced the request for help on Monday, more than a week after records were reported stolen from the Grenoble hospital, where Schumacher was treated for more five months following a ski accident at Méribel resort.
“Nobody has been identified as the author of these acts,” prosecutor Jean-Yves Coquillat is quoted as saying by French-language AFP.
“The investigation continues and is far from having concluded,” said Coquillat, referring to the request by investigators for help from Swiss and German officials.
An individual or group using the name Kagemusha, which claims to have the medical documents, has offered by email to sell them to media for 40,000 euros (60,000 francs), according to German and Swiss news reports.
Kagemusha is an apparent reference to a film by Japanese director Akira Kurosawa.
According to a source close to the investigation, investigators have identified an Internet Protocol (IP) address in Zurich, used by the sender of the emails, Swiss broadcaster RTS reported.
French officials have declined to comment on this information.
Officials from the Swiss department of justice told the ATS news agency they were not immediately in a position to comment on the request for help from the French.
The stolen medical documents consist of a summary report of 11 or 12 pages from the doctor in Grenoble who was treating the seven-time Grand Prix world champion.
The report was reportedly a rough draft rather than the final version of one that was to be transferred to Swiss doctors at CHUV in the canton of Vaud.
Schumacher, 45, ended up in the Grenoble hospital on December 29th after he slammed his head against a rock while skiing off-piste with his son and friends at Méribel, where he has a home.
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He underwent two operations to remove life-threatening blood clots after the freak accident before being plunged into a medically induced coma.
He was transported under top-secret conditions by a Swiss ambulance from Grenoble to Lausanne on June 16th.
Schumacher’s spokeswoman Sabine Kehm said on the same day that he had come out of the coma.
Swiss newspaper Blick reported that Schumacher was “awake” during the ambulance ride and that he nodded to ambulance attendants.
But details of Schumacher’s exact condition have not been made public.