The co-pilot of Germanwings flight 9525 reportedly told his former girlfriend he wanted everyone to know his name

REUTERS/Foto-Team-Mueller

Andreas Lubitz runs the Airportrace half marathon in Hamburg in this September 13, 2009 file photo.

27-year-old German national Andreas Lubitz - described by people close to him on Thursday as a "rather quiet," "polite," and "fun" young man - reportedly told his ex-girlfriend that he was disillusioned with his career at Germanwings.

"He understood that because of his health problems, his big dream of a job at Lufthansa as captain and as a long-haul pilot was practically impossible," his ex, a 26-year-old flight attendant identified only as Maria W., told Bild.

She also told Bild that he told her, "One day I will do something that will change the whole system, and then all will know my name and remember it."

Revelations about Lubitz's battle with depression and a "mental illness" - which he allegedly hid from his employers - came as investigators searched his home for clues about what his motivation could have been for deliberately crashing the plane.

A note found in Lubitz's trash said he was "was declared by a medical doctor unfit to work," Dusseldorf prosecutor Christoph Kumpa said Friday, according to CNN.

His former girlfriend confirmed to Bild that Lubitz had a "problem" which ultimately led them to split up. She noted that when they spoke about work, "he became upset about the conditions we worked under: too little money, fear of losing the contract, too much pressure."

He was also plagued by nightmares and would wake up in the middle of the night screaming, "we're going down," she added, according to the BBC. He was introverted, she said, and knew how to hide his feelings from the rest of the world.

Maria now understands Lubitz's eerie prediction that "one day everyone will know my name."

"I never knew what he meant, but now it makes sense."

Authorities have not specified what illness Lubitz was suffering from that resulted in his being excused from work, but the New York Times has reported that Lubitz was being treated for vision problems prior to the day of the crash. Other evidence recovered from his home suggest mental health issues.

Bild reported on Friday that Lubitz received psychiatric treatment for a "serious depressive episode" six years ago and was having relationship troubles with his girlfriend before the crash.

Lufthansa Chief Executive Carsten Spohr insisted at a news conference on Thursday that Lubitz gave no indication that he was mentally unstable after he resumed his pilot training. If he had an ongoing medical condition, he never revealed it to his employers.

"After he was cleared again ... He passed all the subsequent tests and checks with flying colors," Spohr said. "His flying abilities were flawless."