Andreas Lubitz had searched online for suicide methods and cockpit doors before he crashed a Germanwings flight into a mountain, prosecutors say.
Dusseldorf prosecutors said a tablet computer had been recovered from Lubitz's apartment and they were able to reconstruct searches from 16 March to 23 March.
The prosecutors' spokesman Ralf Herrenbrueck said that search terms included medical treatment, suicide methods, and cockpit doors and their security, according to the Associated Press.
"(He) concerned himself on one hand with medical treatment methods, on the other hand with types and ways of going about a suicide," Mr Herrenbrueck said. "In addition, on at least one day (Lubitz) concerned himself with search terms about cockpit doors and their security precautions."