Those who knew Andreas Lubitz, the co-pilot of the Germanwings plane claim that he was friendly guy.
Those who knew Andreas Lubitz, the co-pilot of the Germanwings plane claim that he was friendly guy.Facebook

Andreas Lubitz, identified as the co-pilot of the Germanwings 4u9525 flight, who crashed the plane intentionally, killing 149 others, suffered from depression a few years ago, and had even taken a break from training in 2009, his friends have revealed. 

Lubitz's mental health has come into sharp focus following revelations by French prosecutors on Thursday that the 27-year-old had deliberately locked the other pilot out of the cockpit and downed the plane in the French Alps. 

While Lufthansa CEO Carsten Spohr said on Thursday that Lubitz did not show any sign of psychological distress, some of the pilot's classmates have revealed that he suffered from a 'burn out syndrome' and depression in 2009, and had taken six months off from training. 

Some of Lubitz's friends made the revelation about his mental health to a Der Spiegel reporter. 

However, some were also reported saying that he never showed any signs of depression. 

"He was happy he had the job with Germanwings and he was doing well," Peter Ruecker, member of a flying club where Lubitz renewed his license last month, told the Associated Press. "He was very happy. He gave off a good feeling."

One reporter also said that Lubitz had plans of marrying his girlfriend next year.

Investigators are now searching for clues from Lubitz's house in Dusseldorf as well as his parents house in Montabaur, where they claimed to have found a "very significant clue." 

While there has been noise around Lubitz's religion, with a reporter asking French prosecutors to reveal the pilot's faith, the latter refused. 

"I don't think it's necessarily what we should be looking for".