well there was something on video that clearly showed the plane doing a smooth maneuver until it was flying horizontal, then dip suddenly. The trees in the shot did not show any strong winds.

Conclusion, something failed at that moment. Pilot, or mechanical.

FWIW the expert on TV pointed out that the maneuver was not called a loop-the-loop but something else. The graphics on TV showed a loop that was not co-planer, there was a twist in it that meant what started parallel to the runway flared-out parallel to the road some 30 deg acute.