The co-pilot of a Germanwings airliner who intentionally brought down his aircraft killing everyone on board appears to have been suffering from depression.

German prosecutors claim Andreas Lubitz hid details about his ill “existing illness and appropriate medical treatment” from his employers. Investigators apparently found torn-up sick notes in his house, including one he had drafted for the day of the crash.

Although they did not name the illness, several reports in German media have said Lubitz had been suffering from severe depression.

All 149 passengers and crew were killed instantly when Germanwings flight 4U 9525 crashed in the French Alps on Tuesday. 

The plane had been en route from Barcelona to Dusseldorf, and flight recordings recovered from the scene revealed how Lubitz began an eight-minute descent after locking the pilot out of the cockpit.

In the recording, the pilot can be heard first knocking lightly on the door and, after being repeatedly ignored, attempting to break it down.

Passengers’ screams can be heard just seconds before the impact, and initial investigations suggest all on board were killed instantly.

Investigators have repeatedly said they do not believe there was any political or religious motive behind the incident.