A Germanwings pilot who ploughed his plane into the French Alps saw 41 doctors in five years, seven of them in the month before the crash, a prosecutor said Thursday in Paris.
Speaking after a meeting with some 200 relatives of the victims in the French capital, prosecutor Brice Robin also announced the probe into the crash was being expanded to see if anyone could be held liable for manslaughter.
Grieving relatives were shown three different reconstructions of what had happened in the cockpit on their trip to Paris to seek answers about the doomed flight, said the head of a disaster support group who attended the meeting.
"The French penal code forbids me from opening a judicial enquiry for murder because the perpetrator is dead," explained Robin at a press conference.
Investigators say that 27-year-old German co-pilot Andreas Lubitz intentionally downed the plane en route from Barcelona to Duesseldorf on March 24.
He is known to have suffered severe depression and the disaster has cast a spotlight on how airline companies monitor the health of their pilots.
Robin said Lubitz, who suffered from "psychosis" and was terrified of losing his sight, consulted 41 different doctors in the past five years.
Stephane Gicquel, the head of the support group, said the "stakes" in the expanded probe were to find out if there had been errors in tracking the mental state of the co-pilot.
"We can clearly see the prosecutor's positioning, to open an enquiry that will pose the question of manslaughter and, very clearly, faults or negligence from Lufthansa in detecting the state of Lubitz's health," Gicquel said.
Several expressed their anger at a delay in the return of their relatives' remains after spelling errors on death certificates.
Some families were left outraged when Lufthansa informed them that repatriation would be delayed due to problems with the issuing of death certificates.
The mayor of the French village of Prads-Haute-Bleone, near the crash site, said there had been slight spelling errors "of foreign-sounding names" on several death certificates.
After a complaint by the families of some schoolchildren killed in the crash, who had already planned funerals, a flight returning their remains went ahead as planned on Wednesday.
However to date the remains of only 44 Germans out of the 150 people killed in the March 24 disaster have been returned home for burial.
A total of 72 Germans were on board the doomed Airbus A320.
Robin said 30 Spanish victims would be repatriated on Monday, and that all remains of the people from 18 different countries would be returned by the end of June.
Investigators only last month finished identifying the remains of all 150 people aboard the flight.
Unidentifiable remains would be placed in a "collective tomb" in the town of Vernet not far from the crash site.