The co-pilot suspected of deliberately flying a Germanwings plane into the French Alps searched the Internet for ways to commit suicide shortly before the crash that killed 150 people, German prosecutors said on Thursday.
Judicial officials in his home town of Duesseldorf said a computer found in his home also had revealed searches on cockpit doors and safety precautions related to them.
The growing evidence of suicide preparations came as French police discovered the second 'black box' flight recorder, raising their hopes of showing in detail how the co-pilot, 27-year-old Andreas Lubitz, set the plane on its fatal course.
If intact, the Airbus A320's Flight Data Recorder would deliver a detailed readout of hundreds of parameters, including any commands issued from the co-pilot's seat during the Duesseldorf-bound flight on March 24.
It is expected to be thoroughly analysed by France's BEA crash investigation authority, which will try to match the data with cockpit voice recordings and information from ground radar.
There is a "reasonable hope" that the data can be recovered intact despite the box's being damaged in the crash, Marseille prosecutor Brice Robin said.
The same prosecutor shocked the aviation world last Friday by alleging that the separate cockpit voice recorder, which was found within hours of the crash, indicated Lubitz had crashed the jet on purpose after barricading himself at the controls.
But investigators are still struggling to understand why Lubitz would take the controls of the Airbus A320, lock the captain out of the reinforced cockpit during a toilet break and steer the jet into a mountainside.
In Duesseldorf, prosecutors said Lubitz had "looked for information on ways to commit suicide" in computer searches that took place between March 16 and 23, one day before the crash.
"On at least one day, the person had for several minutes undertaken searches related to cockpit doors and their safety precautions," they added in a statement.
The German newspaper Bild reported on Thursday that Lubitz had allegedly lied to doctors, telling them he was on sick leave rather than flying commercial planes.
Robin said 150 sets of DNA had been found in the wreckage, corresponding to the number of passengers and crew on board the low-cost carrier's jet.
He stressed, though, that the discovery of 150 DNA sets did not mean that all the victims had been found.
At each matching of a DNA set to a victims, families will immediately be informed, he told reporters in Marseille.
In addition, 470 personal items have been found. They included 42 mobile phones, but Robin said they looked unlikely to yield much useful.
"These telephones are in a very, very damaged condition, which will certainly make extracting information from them very, very difficult," he said.
After a nine-day hunt, the second data recorder was found by a French gendarme in a ravine, buried 20 centimetres down in a place that had been searched several times already, Robin said. It had caught fire and was blackened and damaged.
Black boxes -- which are actually bright orange -- are designed to withstand temperatures of 1,100 degrees Celsius for up to an hour, according to manufacturer Honeywell.
Germanwings parent Lufthansa said it welcomed the discovery of the second box and hoped it would yield results.
The airline has come under pressure to explain what it knew about the co-pilot's history of depression and could face substantial claims for damages, according to legal experts.
It said this week that when Lubitz resumed pilot training after a break in 2009, he provided the company flight school with medical documents showing he had gone through a "previous episode of severe depression".
