I am not an accident investigator so cant say for sure but know that a prop under load bends forwards on ground contact. Its to do with most of the thrust being generated in the outboard region of the blades not by the hub. I have flown many types of prop aircraft and when I start on a new type I read lots of accident investigations on the NTSB database relating to that type. They determine that an engine is under load by looking at the damage to the engine internals and also the prop, if it is bent forwards it was under load, if it is not it was probably not producing much thrust.