Investigators have found the “black boxes” from the debris of this week’s fatal French military helicopter crash and authorities will soon start examining them, a military spokesman said on Wednesday.

Colonel Frederic Barbry also told French TV station BFM TV that the bodies of the 13 dead French soldiers would soon be repatriated to France.

The soldiers died in Mali on Nov. 25, when their helicopters collided as they hunted in the dark for Islamist militants.

It was the biggest loss of French troops in a single day since an attack in Beirut 36 years ago when 58 soldiers died.