BERLIN — Doctors consulted by the pilot who crashed Germanwings Flight 9525 considered him unfit to fly, but withheld the information from his employer because of strict German privacy laws, a French prosecutor said Thursday.

Brice Robin, the public prosecutor from the French city of Marseille, announced the opening of an official criminal inquiry into the crash while offering fresh insights into the series of events that allowed a deeply troubled pilot named Andreas Lubitz into the cockpit on March 24. Robin said there is no longer a “shadow of a doubt” that the 27-year old deliberately flew the plane, en route from Barcelona to Dusseldorf, into a mountainside, killing all 150 people on board.

Lubitz, Robin said, had consulted doctors out of fears that he was going blind — something that would have grounded the young pilot who had a lifelong ambition to fly commercial jets. He had seen seven doctors in the 30 days prior to the March 24 crash, Robin told reporters in Marseille, according to The Associated Press.

The visits included at least three appointments with a psychiatrist. Lubitz was determined by some of the doctors he consulted to be psychologically unstable, and therefore unfit to fly, but “unfortunately, that information was not reported because of medical secrecy requirements,” Robin said, according to AP.

According to a joint report on Thursday from the German daily Süddeutsche Zeitung and TV networks NDR and WDR, an analysis of Lubitz’s iPad showed that in March, he was searching the Internet for ways to purchase a deadly drug cocktail of valium and potassium cyanide. He was also reportedly looking for information on legal end-of-life provisions — apparently worried that a suicide attempt could fail.

Germany maintains some of the strictest privacy laws in the world, with doctors facing high fines and possible imprisonment for breaking patient confidentiality. The French prosecutor’s charges are likely to cause repercussions in Germany, where a public debate is continuing over whether any of its laws — including privacy laws — should be re-examined after the crash.

Robin made the announcement on the same day he met with the families of victims, some of whom are still waiting for the remains of the bodies of loved ones. On Wednesday, mourners lined the streets of the German city of Haltern, home to 16 schoolchildren on a field trip who died on board the flight. The coffins, in white Mercedes hearses, rolled down city streets lined with schoolmates and mourning local residents.

Peter Kortas, a German lawyer representing 34 victims, said families had been upset about the long delays in transporting the remains of their loved ones. Although most of his clients have received the remains, they did so only several days ago and had been feeling “frustrated” and “all the bad feelings you can imagine.” He said Germanwings and its parent airline Lufthansa had initially informed some families that remains would be forthcoming, only to later inform them of delays due to clerical errors.

Talks on compensation, he said, had opened this week. He said he was unable to offer more detail due to a confidentiality agreement.

A spokeswoman from Lufthansa referred calls to Germanwings. Germanwings spokesman Heinz Joachim Schöttes defended the delays in returning victims to their families, saying “we had to find out ourselves what kind of inconsistencies had occurred. Subsequently, we immediately communicated this to the relatives.”