Finally saw a photo of the left side of the fuselage, showing external fire damage in the area just behind the LMG, damaging the wing and the fuselage in that area. Lools like maybe a not too large fuel fire in this area from a leak as a result of the hard landing. I guess this spread to the cabin and cargo, or maybe an internal fuel leak occurred as well.
So with more photos to look at, this looks like a hard landing after all, just as the investigators have been saying.
So what caused the hard landing?