German prosecutors say the co-pilot of the Germanwings passenger plane that crashed in the French Alps had received treatment for suicidal tendencies.

Duesseldorf prosecutors say that Andreas Lubitz received psychotherapy "with a note about suicidal tendencies" for several years before becoming a pilot.

Prosecutors' spokesman Ralf Herrenbrueck said Monday that investigators have found no indication of a motive so far as to why Lubitz crashed the plane, nor any sign of a physical illness.

All 150 people on board died in the crash.