The French authorities have begun new investigation into negligent homicide over the Germanwings crash in March which claimed 150 lives.
The prosecutor, Brice Robin, said in Marseille on Thursday, June 18, that proceedings are taking place against "unknown" parties.
The aim is to establish whether Germanwings and its parent company, Lufthansa, bear responsibility for the disaster in the French Alps.
He said on Monday that there was currently insufficient evidence to open negligence proceedings against either Germanwings or Lufthansa.
Meanwhile, German investigators said on Friday that the co-pilot, Andreas Lubitz, 27, whom French investigators said deliberately flew flight 4U9525 into a French mountain, remains the sole accused in Germany's inquiry into the crash.
Lubitz was said to have suffered from a raft of ailments that apparently had no physical cause and he had been to seven medical appointments, including with psychiatrists, in the month before the crash.
Prosecutors said Lubitz searched online for ways to poison himself before the crash.