The German man behind the massacre of Germanwings Flight 9525 was once treated for suicidal tendencies.
According to the Chicago Tribune, Dusseldorf prosecutors have revealed that a number of years before he earned his pilot's license, 27-year-old Andreas Lubitz was given "a note about suicidal tendencies" from a mental health professional.
Prosecutors' spokesman Ralf Herrenbrueck revealed in a written statement,
Lubitz took a six-month break from pilot training in 2009 and was treated for anxiety and depression for over a year.
Investigators found numerous, torn-up doctor's notes inside Lubitz's home stating he was deemed unfit to fly on the day of last week's tragedy.
It isn't clear what drove Lubitz over the edge but the it's possible he recently broke up with his girlfriend.
Friends described him as a polite, studious individual who had grown increasingly quiet as of late.
Audio recordings from the flight support the theory that Lubitz locked his captain out of the cockpit and disregarded his requests to open the door before intentionally crashing the plane into the French Alps.
The 150 people on board are said to have died instantly.
Three Americans were on the flight.
Many European airlines have since implemented a new rule requiring two crew members to be in the cockpit at all times.
The US implemented the same policy for its airlines several years prior to this incident.