Duesseldorf: The co-pilot believed to have deliberately crashed a Germanwings plane into the French Alps was classified as suicidal "several years ago" but had appeared more stable of late, German prosecutors said.
As investigators in both countries tried to zero in on a potential motive, it emerged that that the first officer, Andreas Lubitz, was receiving treatment from neurologists and psychiatrists who had signed him off sick from work a number of times.
However doctors had recently found no sign he intended to hurt himself or others, said Ralf Herrenbrueck, spokesman for the prosecutor`s office in the western city of Duesseldorf, on Monday.
Meanwhile investigators sifting through the wreckage and hundreds of body parts in the French Alps were forced to resume the hunt on foot as bad weather hampered helicopter flights.
"The teams will get to the site via the path that is already in existence," said Yves Naffrechoux from the local mountain police.
Authorities are hoping to identify more DNA from the 150 people who died, as well as locate the jet`s second black box that should provide more clues as to the circumstances of the tragedy.
Forensic teams have isolated almost 80 distinct DNA strands from the shattered aircraft and have described the grim task as "unprecedented" given the tricky mountain terrain and the speed at which the plane smashed into the rock.
Investigators evaluating voice recorder data say co-pilot Lubitz allegedly locked his captain out of the cockpit and slammed the plane into a French mountainside last Tuesday.
The flight, en route to Duesseldorf from Barcelona, crashed at a speed of 700 kilometres (430 miles) an hour, instantly killing all on board.Fending off an international media frenzy, Herrenbrueck, of the Duesseldorf prosecutor`s office, criticised conjecture about Lubitz`s alleged motives and said German authorities would not take part in "speculation".
Herrenbrueck said, based on the evaluation of medical documents and the testimony of people who knew the co-pilot, there was still no indication that he had told anyone of his plans or left behind a suicide note.
"Nor have particular circumstances been identified in his personal or professional environment to offer verifiable evidence about a possible motive," he said.
Medical files did not point to any "organic disorder", Herrenbrueck said.
But he added that Lubitz underwent psychotherapy several years ago, before he became a pilot in 2013, "for a long period due to diagnosed suicidal tendencies".
However it said his doctors had found nothing recently that could have pointed to the events of last Tuesday.
Media reports have emerged that the 27-year-old was taking medication for severe depression and was being treated for problems with his vision, possibly for a potentially career-ending detached retina.Authorities say the working conditions at the inhospitable crash site have hugely slowed their progress.
Not a single body is intact, said Patrick Touron, deputy director of the police`s criminal research institute.
"We have slopes of 40 to 60 degrees, falling rocks, and ground that tends to crumble," he said.
"Some things have to be done by abseiling. Since safety is key, the recovery process is a bit slow, which is a great regret."
Between 400 and 600 body parts were being examined, Touron said.
Authorities are hoping to build a more sturdy road to the crash site -- both to ease access for forensic experts and for families who want to see where their loved ones perished.
A bulldozer and several specialised machines were already working away at the site to bolster the road access.
The director of operations at Germanwings, Oliver Wagner, told reporters that 325 grieving relatives had so far made the trip to the village of Seyne-les-Alpes, close to the crash site.
"The majority has been German and Spanish families but we`ve also had people from Mexico, Japan, Colombia, Venezuela or Argentina," he said.
Wagner said Germanwings and parent company Lufthansa had 90 people on the ground to care for the families, including around a dozen psychological counsellors.
He reiterated that the company had announced it would immediately compensate each family with 50,000 euros ($54,000).
This sum would not be deducted from any final compensation deal, he stressed.
On Monday evening, an ecumenical prayer service in memory of the 150 crash victims drew hundreds of diplomats and believers to the German church in Rome, Santa Maria dell`Anima.
Since the first details emerged of the circumstances of the crash, numerous airlines have ordered two airline crew to be present on the flight deck at all times.
Also on Monday, Mexico became the latest country to impose on its airlines the so-called "rule of two," which is standard in the United States.