Just over a week after a Germanwings plane crashed into the French Alps, investigators have finished retrieving human remains from the crash site and are now trying to match them with DNA profiles from the 150 people killed – an arduous task that could leave families waiting for months.

The extraordinary recovery process mobilized hundreds of people and cut a stony road into a forested Alpine mountainside to help the team bring back anything they found, from a body part to a tiny shred of skin. Not a single intact body was found.

Francois Daoust, head of the France’s IRCGN national criminal laboratory in Pontoise outside Paris, said that as of Monday afternoon the forensic teams on the site and in Paris had isolated 78 distinct DNA profiles from the hundreds of samples recovered at the site – leaving nearly as many unaccounted for.

Meanwhile, they had only received complete DNA profiles for about 60 victims from their relatives because it takes time to gather samples from families still reeling from their loss.

Based on black box cockpit recordings recovered the day of the crash, investigators believe the Germanwings co-pilot, Andreas Lubitz, locked the captain out of the cockpit and deliberately slammed the plane into the mountain, killing everyone on board.

The impact of the March 24 crash shattered the plane and all those inside, ripped a black box from its orange protective casing, and left shreds of metal and cloth scattered across hundreds of meters (yards).

Lt. Col. Jean-Marc Menichini, who has been involved in the operation focusing on recovering victims’ remains, said Wednesday “there are no longer any visible remains” at the crash site.

A special unit of mountain troops, with help from German investigators, is now clearing the crash site of everything else that is there – including debris and personal effects.

While the retrieval of DNA from the body parts may be completed as early as this week, Daoust said it would take two to four months to match the samples with the victims’ DNA profiles.

Dental and surgical records, tattoos, DNA from hair- or toothbrushes – will all serve to identify and ultimately return the remains to families.

Daoust said all the families will be informed at the same time who has been identified.

“If I announced an identification as soon as I had it to a family, psychologically it’s an oppression and a pressure on those that don’t yet have an identification,” he said.

If some victims have still not been identified when everything possible has been done, it will be horrifying for those families, but they will understand investigators did all they could, he added.

Jim Hall, a former chairman of the American National Transportation Safety Board, said France’s timeframe for recovering and identifying victims seemed ambitious. Hall oversaw the 1996 crash of a ValuJet flight into the Florida Everglades that killed all 110 aboard, and said that recovery operation – similarly perilous and complex – took weeks, if not months.

“Nothing is more important to the families and to our culture and respect for human life than to perform that function in a deliberate and responsible fashion,” Hall said.

Lufthansa acknowledged Tuesday that it knew six years ago that Lubitz had suffered from an episode of “severe depression” before he finished his flight training at the German airline, but said he had passed all his medical checks since then.

On Wednesday, the chief executive of Germanwings’ parent company Lufthansa said it will take “a long, long time” to understand what led to the crash – but refused to say what else the airline knew about the mental health of the co-pilot and why they haven’t released more information about it.

Lufthansa CEO Carsten Spohr and the head of its low-cost airline Germanwings, Thomas Winkelmann, visited the crash area Wednesday.

German prosecutors say Lubitz’s medical records from before he received his pilot’s license referred to “suicidal tendencies,” but visits to doctors since then showed no record of any suicidal tendencies or aggression against others.

The revelations intensify questions about how much Lufthansa and its insurers will pay in damages for the passengers who died – and about how thoroughly the aviation industry and government regulators screen pilots for psychological problems.

The second black box containing the plane’s mechanical and instrument readings – crucial for learning how the plane was set on its doomed course – has not yet been recovered.

On Tuesday, German daily Bild and French magazine Paris Match said their reporters have been shown a video they say was taken by someone inside the cabin of the doomed plane shortly before it crashed, where passengers can be heard screaming “My God” in several languages.

The Associated Press could not independently confirm the reports.

Marseille Prosecutor Brice Robin, overseeing the French criminal investigation into the crash, told the AP that no cell phone video has been found from the plane.

(AP)