French investigators on Friday said data from the black box showed that the co-pilot had deliberately accelerated the plane several times as it descended toward destruction.

"A first reading shows that the pilot in the cockpit used the automatic pilot to descend the plane toward an altitude of 100 feet (30 meters). Then, several times during the descent, the pilot changed the automatic pilot settings to increase the aircraft's speed," the BEA crash investigator office said in a statement.

The second flight recorder was found on Thursday following a nine-day search at the crash site, after data recovered from the first black box, a voice recorder, had already suggested the co-pilot's role in bringing about the crash, in which 150 people lost their lives.

Co-pilot Andreas Lubitz is thought to have deliberately locked the captain of the flight out of the cockpit before intentionally flying the Airbus into the ground.

German state prosecutors said on Thursday that information retrieved from a computer belonging to Lubitz showed that someone had conducted Internet searches about safety measures on cockpit doors and about suicide methods in the weeks preceding the crash.

Previously, they said the 27-year-old had been diagnosed as suicidal before becoming a pilot. Lubitz informed Lufthansa, of which Germanwings is a subsidiary, about his illness in 2009 after interrupting his flight training.

A report in the German news magazine Spiegel said on Friday that prosecutors in Düsseldorf had visited a number of doctor's practices where Lubitz had sought treatment, and taken his medical files for examination.

The prosecutors said the doctors included neurologists and psychiatrists, according to Spiegel.

tj/sms (AFP, AP)