Investigators probing the crash of an Air Algerie flight in Mali that killed 116 people last month say they have been unable to access voice recordings from the flight deck.

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“The tape was a little bit damaged. We were able to extract it… The BEA laboratory was able to restore the tape. Unfortunately the recordings are so far unusable,” Remi Jouty, the head of France’s Bureau of Investigations and Analyses (BEA) air safety agency, told journalists on Thursday.

Flight AH5017, a McDonnell Douglas 83 jet that took off on July 24 from Ouagadougou in Burkina Faso bound for Algiers, crashed in the Mali desert after asking to turn back as bad weather struck.

France bore the brunt of the tragedy, with nearly half of the victims.

Other passengers came from Burkina Faso, Lebanon, Algeria, Spain, Canada, Germany and Luxembourg.

Jouty said it seemed likely that the plane had broken up on impact instead of in the air.

“When we look at the trajectory, this leads us to believe that the plane did not break up into several pieces while in flight. This does not exclude that damage was caused during the flight,” he said.

“I don’t think we can at this point exclude the possibility of a deliberate act but we cannot say more for the moment,” he said.

N’Faly Cisse, the head of Mali’s civil aviation accident commission, told the press conference that the BEA would hand in a fresh progress report in mid-September.