Material science tech here.
I would bet you lots of money that this is due to material failure. Most likely manufacturing issue, like the Sioux event.
Pictures tells me the fracture edges are sharp and clean which suggests rapid phase change in the material, to the point of breaking.
The initiating event might have been a smaller fracture in f.ex. a fan blade (or what else floats your boat) and the accompanying force redistribution was enough that the flawed crystal structures said bye bye and left the building with the entire front attached.