Germanwings co-pilot Andreas Lubitz, who deliberately crashed Flight 9525 in the French Alps in March, researched deadly drugs and looked up the term "living will," German prosecutors confirmed Friday. The findings give rise to speculation that Lubitz may have considered other means of committing suicide before the crash.

In March, the 27-year-old searched on the Internet about ways of getting access to drugs like potassium cyanide, valium and lethal combinations of medicines, Dusseldorf prosecutor Christoph Kumpa said, confirming a report in German daily Sueddeutsche Zeitung, the Associated Press reported. Lubitz also reportedly searched the term "living will" -- a legal document that states a patient’s wish for medical care if he is unable to communicate with doctors -- a day before the crash. In April, German prosecutors had said that Lubitz had researched suicide methods and the security of cockpit doors.

On Thursday, Marseille prosecutor Brice Robin said that information obtained from Lubitz's tablet computer found in his apartment, showed he had also looked up vision problems and "feared going blind," which would have ended his aviation career. Robin reportedly said that doctors who had seen Lubitz felt he was mentally unfit to fly, adding that Lubitz had seen seven doctors in the month leading up to the March 24 crash, including three appointments with a psychiatrist. Authorities had earlier said that Lubitz was suffering from depression and had been treated for psychological problems. 

Flight 9525 was traveling from Barcelona to Dusseldorf with 150 people, when Lubitz initiated the plane's descent, ensuring it plunged into the mountainside, after locking the captain out of the cockpit. German and French prosecutors are reportedly investigating the crash that killed everyone on board, including Lubitz.

French prosecutors reportedly announced a preliminary investigation into whether manslaughter charges should be brought over the crash. However, it was unclear who the charges would target.