So what part would the police know that is not apparent in the minimal facts presented?
It was a training flight.
They were practising procedures for forced landing.
The engine stopped for real and CASA called it engine failure.
Given it was a instructor, we will assume they quickly did all the correct checks of mags, fuel etc, which they had been practising prior to engine failure.
They recognised the engine had failed. Thus it was a real event.
They continued to aviate then communicate a ",mayday".
They avoided all public ie didn't try to land in a house or road nor do anything silly like stall it when turning.
They picked the best available landing spot that was in glide range.
They ensured they cleared the houses and any possible obstacles like power lines.
The managed the speed and decent rate to avoid landing too short or long of the intended landing spot.
They did not become fixated with the tree in the paddock.
They executed a perfect landing.
They exited the aircraft once stopped.
The instructor and student are unharmed.
The aircraft is undamaged, subject to a careful check over and obviously determination of the cause of the engine failure. And rectification/ rebuild? Etc
The ATSB will determine why the engine failed.
Or are you assuming either the pilot in command made a significant error causing engine failure or the student did. And then told the police they caused the engine failure?
They ran out of fuel and told the plod as such?
Or that the plod due to his immense experience chasing cars, catching criminals and saving little old ladies from holigan bike riders. Was able to determine some fault in piloting or that he would have done better.
Or maybe I didn't read where he was a aviation expert?
Irrespective of the actual cause of failure, which is yet to be determined- they did exactly what they trained and executed it perfectly.
Maybe plod expected them to repel the forces of gravity as well.