Best video of crash scene so far.
It appears the Helicopter experienced a catastrophic failure of some kind while in flight and shed parts on the way down.
Cause of the failure or suspected cause has not been determined.
Though not seen in the video...the Main Rotors seem to be further away than the Tail Rotor and Vertical Stabilizers.
The NTSB Official described the wreckage trail being about 2000 feet long.
https://www.whec.com/rochester-new-y...crash/6456860/