the turbine blades look like they melted. This probably occurred in flight and indicates that the engine was on fire before the impact. The turbine blades are coated with heat resistant ceramics. It could have melted from a post crash fire but the ground around it doesn't look burnt.
the turbine blades take energy from the combustion section to turn the accessories and compressor section of the engine. the blades are designed to for high heat, but not sustained. The engineering relies on rapid cooling to not melt. So what my point is is that either the engine failed and there was a fire, or there was a fire and the engine failed. Likely in flight, unless there is evidence of a post crash fire.