As the investigation continues into the crash of a Germanwings passenger jet into the French Alps, investigators have revealed that the crash of the jet was directly attributable to the co-pilot of the jet, who investigators say crashed the jet intentionally, into the mountains.

Investigators are basing their findings on the information gleaned from one of the aircraft’s flight recorders, and say the co-pilot, Andreas Lubitz, who has only been flying with the airlines for two years, put the aircraft into a gradual decent into the mountainous terrain.

According to the investigation, the pilot of the aircraft had exited the cabin to use the latrine, and upon his return, Lubitz refused to open the cockpit door to let him back in. The flight recorder, when played back revealed the sounds of the pilot knocking, then attempting to break down the door as passengers could be heard screaming in the background just moments before impact.

During the entire episode, the flight recorder recorded the co-pilots breathing patterns and nothing untoward could be discerned. He did not speak a single word as he was locked inside the cockpit, and made no sound as the pilot worked to re-gain entry. He did not reply to any of the calls from French Air Traffic Controllers, who attempted to contact the aircraft as it descended below radar before its crash.

While the aircraft has a touch keypad that can be accessed by flight crew to gain access to the cockpit, that keypad can be over-ridden for five minutes at a time by the pilot/co-pilot from inside the cockpit to refuse access to that area.

Investigators have as yet to release information as to the motives behind the 28-year-old’s actions, and have since gone to his residence to search for any evidence as to why he crashed the Airbus A320, killing 150 passengers.

Lubitz had begun his airline career as a steward, then changed careers, going to pilot training school, then joining the airlines directly after. He had 630 hours of flying experience.

Authorities say that Lubitz suffered from depression in 2009, but decline to say if that bout of depression lingered and was directly responsible for his actions on Tuesday. Investigators do say, however, that Lubitz did not have any known ties to terrorism networks.

Investigators are continuing to comb the debris field left by the crash in search of the aircraft’s second black box.

  airbus a320, andreas lubitz, co-pilot, crash, depression, french alps, germanwings, intentional