LN81  

Doorbell cameras confirmed the fenestron was at least being driven as it's audio was very clear. Control continuity was confirmed by ntsb on all controls including the tail. At this point it's down to the hydraulic system/servos making a control input that couldn't immediately be held back by the pilot. All parts of the aircraft made it to the landing site and are accounted for so no major CG change by a loss of component or aerodynamic change by loss of stabilizers. The bang part....hard to say, if a servo suddenly commands a full deflection of a control at maximum extension speed that may itself make the bang sound. Thankfully everyone is alive and aircraft intact so they can pull everything apart on a bench and download all the data and come up with a reason.  

there Is another doorbell camera from the house directly behind the 1st cameras. Cam1 saw the descent and leveling off above tree line with some pitch oscillations before aircraft flew overhead The camera. Cam2 shows aircraft straight and level at maybe 200' agl heading southeast towards the crash site. Whatever major control malfunction occurred the pilot had it at least somewhat under control. Then cam3 shows the impact which seems harder than one would expect with both engines running unless the controls failed again in a way that didn't allow the pull the pilot planned on to finish the landing. For the fellow 135 drivers out there the idea that a new failure mode may have occurred causing the aircraft to roll and then further loss of control is not exactly the warm and fuzzy feeling you want while the ntsb hopefully finds an answer.