Air crash investigators examining a computer belonging to Germanwings co-pilot Andreas Lubitz are trying to determine whether the killer 'spiked ' his captain 's drink to force him into the toilet . Lubitz , 27 , crashed the Airbus A320 passenger jet into the Alps changing the aircraft 's altitude to just 100 feet using the autopilot , sending it on collision course with the Alps . German prosecutors believe that Lubitz may have added a chemical to Captain Patrick Sodenheimer 's coffee to remove him from the flight deck . Scroll down for video . Andreas Lubitz may have spiked his Captain 's coffee so he would be left alone on the aircraft 's flight deck . Investigators have been scouring Lubitz 's computers to determine his state of mind before the tragedy . Lubitz remained silent during the final eight minutes of the flight as it flew into the Alps . Once Captain Sodenheimer closed the cockpit door , Lubitz enabled special security features preventing the reinforced door from reopening . The safety systems were introduced following the 9/11 attacks although the designers did not consider a rogue pilot seeking to kill himself while taking his passengers and fellow crew with him . Already it has emerged that Lubitz used his computer to research methods of killing himself as well as information concerning the cockpit door locking mechanism . It is understood that European safety chiefs had concerns about Germanwings ' safety procedures in the weeks before the crash . In November 2014 , the European Commission contacted several airlines and 'had asked for clarification to make sure all airlines actively observe rules ' . Following the crash , it emerged that Lubtiz suffered from crippling depression although Lufthansa , who own Germanwings , did not pass on this information to aviation regulators . Investigators believe that Lubitz , 27 , informed its flight school when he returned from a several-month break in pilot training in 2009 that he had experienced an episode of 'severe depression ' . Lufthansa has said he subsequently passed all medical tests . The EU has detailed air safety regulations , which included rules on a pilot 's mental health , that member states need to take into account . EASA regularly tests whether the 28 EU nations adhere to those standards . 'This is a normal and regular occurrence , ' said the official .
Investigators have been searching Andreas Lubtiz 's internet search history . Lubitz sought information online on various methods of taking his own life . He is also believed to have researched the cockpit door locking system . Investigators now want to determine why the captain left the cockpit .