What we do and do not know about Germanwings co-pilot Andreas Lubitz

Andreas Lubitz is the co-pilot who prosecutors believe "intentionally" crashed a commercial flight into the French Alps, killing himself and 149 other people.

Today prosecutors in Germany said the 27 year old had been treated for suicidal thoughts "several years" before qualifying.

“Until recently, further visits to doctors who gave him sick leave have taken place where no feelings of suicide or aggression towards other people were found,” Ralf Herrenbrück said.

The investigation into the crash is ongoing, but here is what we do and do not know about Lubitz.

What has been reported

• Lubitz was expecting a baby with his parter, who is a teacher.

• He told his ex-girlfriend, identified as Mary W, that one day "I will do something that will change the whole system and then all will know my name and remember it."

• Mary, a member of an airline cabin crew, said Lubitz had suffered from nightmares.

• He may have had a detached retina, a condition which can cause blindness if left untreated The French newspaper Le Figaro quotes a French security source as claiming his sight had been already reduced “by at least 30 per cent”.

• Dusseldorf hospital confirmed it treated Lubitz in February and March, but not for depression.

• Black box recordings indicate Lubitz had urged Flight 4U 9525's pilot to go to the lavatory during the flight. That's when it is thought he locked him out of the cabin and deliberately crashed the flight.

• A member of Lubitz's local flying school said on Saturday he was familiar with the French Alps and was even “obsessed” with the region.

• According to black box data he said "we'll see" while discussing landing checks for the plane.

Local people remember the victims of the Germanwings crash

What we do know

• Lubitz concealed a sick-note declaring himself unfit to work on the day he is thought to have crashed the Airbus A320.

• The 27-year-old was being treated by “several neurologists and psychiatrists” and had a "psychosomatic" illness. It is believed he kept this from his employers.

• Police said they also found large amounts of medication needed to treat depression in the pilot’s Düsseldorf flat.

• He was a German citizen and he did not say a word after apparently locking his pilot, named as Patrick Sonderheimer, out of the cockpit.

• Friends have described him as a "rather quiet" but friendly man.

• He trained with Germanwings' parent company Lufthansa in Bremen.

• Lubitz interrupted his training for an "unexplained" break in 2008, it's thought that this was because of depression. He then re-took psychological tests before qualifying as a pilot.

What we don't know

• If the tragedy was pre-planned.

• What could have possibly motivated it or influenced Lubitz, if he was the one who was responsible.

• The full details of the illnesses Lubitz was suffering from, if any.

• The full sequence of events before the crash and why he appears to have locked his pilot out of the cabin.

More: Here's how the Germanwings pilot could have been locked out of the cockpit

Additional reporting: Independent journalists