Doctors who had seen the co-pilot who crashed a Germanwings jet in late March, killing all 150 people onboard, felt he was mentally unfit to fly, a French prosecutor said Thursday, according to the Associated Press. Marseille Prosecutor Brice Robin told reporters that Andreas Lubitz had seen seven doctors in the month leading up to the March 24 crash, including three appointments with a psychiatrist.

The doctors did not warn the pilot's employers, however, because of German patient secrecy laws. Robin said that some doctors felt Lubitz was unfit because of his psychological state, but "unfortunately that information was not reported because of medical secrecy requirements," the AP reported. German doctors could potentially go to prison for disclosing patient information unless there is evidence the person intends to commit a serious crime or harm themselves.