[SEYNE-LES-ALPES] Dozens of specialised police and rescue workers kicked off a fourth day of recovery operations on Friday at the scene of the crashed Germanwings jet, hunting for its second black box.
Officials are also combing the wreckage for body parts and DNA samples that would enable them to identify the 150 people that died in the crash, apparently deliberately initiated by co-pilot Andreas Lubitz.
"We're first collecting biological elements, then debris," said a police spokesman.
The vast majority of the bereaved family members have now left the remote site in the French Alps where the Germanwings Airbus A320 smashed into the mountain.
French prosecutors said on Thursday that Lubitz "deliberately" initiated the descent and seemed to "want to destroy" the plane in an act that German Chancellor Angela Merkel described as "unimaginable."
Germany and Spain bore the brunt of the tragedy, with 75 Germans dead and at least 50 Spanish on board the Barcelona to Duesseldorf flight.
French Prime Minister Manuel Valls said that "everything is pointing towards an act that we can't describe: criminal, crazy, suicidal."
"It's up to the legal investigators - especially the Germans and of course Lufthansa - to shed light on the career and profile of this pilot," said Mr Valls.
French prosecutors have been able to listen to the voice recordings in the cockpit before the crash but are still searching for the second black box that contains technical flight data.