The second black box from the ill-fated Germanwings plane has been found, a French prosecutor said on Thursday.

Following a nine-day search, the flight data recorder has been recovered from the crash site in the French Alps, the prosecutor said, according to AFP news agency.

Investigators hope the second of the black boxes of  Germanwings Flight 4U9525 could provide valuable information about the final moments of the plane.

The Airbus A320 crashed into a mountainside in the French Alps some 100 km north of Nice less than an hour after taking off from Barcelona in Spain on a flight to Duesseldorf in Germany.

Citing cockpit voice recordings from the first black box, which was recovered last week, prosecutors have said they think co-pilot Andreas Lubitz had locked the pilot out of the cockpit and deliberately crashed the plane, instantly killing all 150 people on board.

The second black box records technical flight data and could provide vital information about the plane’s final moments before it slammed into the remote mountainous region at a speed of 700 kilometres an hour. The force of the impact and the extremely difficult terrain have hampered the search for evidence.

In a related development, German state prosecutors have said a computer seized from Lubitz's home showed the co-pilot had made Internet searches for suicide methods and cockpit door security, according to Deutsche Welle.

Marseille prosecutor Brice Robin, a lead French investigator into the crash, is expected to give a news conference with additional details later on Thursday.