The co-pilot of Germanwings Flight 9525 that crashed into the French Alps last week had received treatment for suicidal tendencies several years ago, prosecutors said Monday.

Duesseldorf prosecutors say co-pilot Andreas Lubitz, 27, had received psychotherapy "with a note about suicidal tendencies" for several years before becoming a pilot.

"In the following period, and until recently, further doctor's visits took place, resulting in sick notes without any suicidal tendencies or aggression against others being recorded," prosecutors' spokesman Ralf Herrenbrueck said in a written statement.

Authorities believe, based on data from the plane's cockpit voice recorder, that Lubitz locked his captain out of the cockpit and ignored his pleas to open the door while manually sending the plane into a fatal descent on what should have been a routine flight.

Prosecutors said they have so far found no indication of a motive that might have prompted Lubitz's actions, nor any sign of a physical illness.

Asked about reports that Lubitz had problems with his vision, Christoph Kumpa, another spokesman for the Duesseldorf investigators, said there was no documentation showing that Lubitz had any physical ailment affecting his sight.

All 150 people on board were killed when the Airbus A320 plane flying from Barcelona to Duesseldorf slammed into a French mountain on March 24.

Minute by minute, the demise of doomed German flight

Here is a look at the short journey and violent end of the German budget airline flight that crashed into the French Alps with 150 people aboard, based on information from French accident investigators, government officials and the airline Germanwings, a subsidiary of Lufthansa:

Times listed are Central Europe Time

Monday, March 23

The plane, a Germanwings Airbus A320, undergoes a routine safety check at Duesseldorf Airport.

Tuesday March 24

8:57 a.m.

The 24-year-old A320 single-aisle jet arrives in Barcelona from Duesseldorf.

10:01 a.m.

Germanwings Flight 9525 takes off from Barcelona, slightly delayed because of airport congestion, for the return trip to Duesseldorf, about 1,300 kilometers (800 miles) away.

Aboard were 144 passengers, two pilots and four cabin staff. Among them: babies, a group of German high-school students, an American contractor and her daughter, three generations of the same family.

10:30 a.m.

The pilots make their last contact with air traffic control in a routine message seeking and obtaining permission to continue course. At the time, the aircraft had reached its cruising altitude of 38,000 feet, and was over the Mediterranean Sea approaching the region around Marseille.

10:31 a.m.

The plane begins its unexplained descent above the French coast, just as its flight path crosses over land.

10:35 a.m.

Air traffic controllers try to contact the pilots, but receive no response.

10:40 a.m.

The last radar position of the plane is registered, at 6,175 feet - only slightly higher than the peaks of the southern French Alps below. The French Air Force sends a Mirage fighter jet to the plane's last known location. An air force official says the Mirage arrived too late to help, and never crossed paths with the A320.

About 12 noon

Rescuers in helicopters spot the debris, scattered across a ravine and the slopes of the Col de Mariaud. Amid the pulverized remains, there were no survivors.