(Reuters) French prosecutors say 28-year-old German co-pilot Andreas Lubitz locked himself in the cockpit and adjusted the altitude setting on the Airbus A320, sending it plunging from its cruise altitude of 38,000 feet at a rate of 3,000 feet a minute.

The German citizen, left in sole control of the Airbus A320 after the captain left the cockpit, refused to re-open the door and pressed a button that sent the jet into its fatal descent, the prosecutor told a news conference carried on live television.