I saw the various "videos" of this crash on the news. What bothered me about the videos was the almost totally downward trajectory of the aircraft and the speed at which it was going.
It appeared to be in a full power dive. That is hard to fathom, for me, to be a "Pilot Error".
Again, I am not a pilot. But I understand a little about the way an aircraft works. To go nose down would seem to require a movement of a control and, like I said above, it appears there was no attempt to decrease the speed or bring the aircraft's nose up.
With no other information that what has been provided, one should probably assume the aircraft was pilotless and under full power. No idea why.
I don't believe either pilot was suicidal but, one never knows.
Rams