BERLIN (AP) — German prosecutors say the co-pilot of Germanwings Flight 9525 appears to have researched suicide methods and cockpit door security in the days before the plane crashed last week.

Duesseldorf prosecutors said Thursday investigators found a tablet computer at Andreas Lubitz's apartment. They said they were able to reconstruct searches from March 16 to March 23.

Investigators believe the 27-year-old Lubitz locked his captain out of the A320's cockpit on March 24 and deliberately crashed the plane. All 150 on board died.

Prosecutors' spokesman Ralf Herrenbrueck said in a statement that search terms included medical treatment and suicide methods. On at least one day, the co-pilot looked at search terms involving cockpit doors and their security methods.