The distance and clothing would have made a taser employment pretty difficult. Had the hit that took him down been a taser, then he should have moved after the Taser power cycle was over, 5 seconds after trigger release. I think he fell to the snow from a devastating gunshot wound, head, neck, or spine.
The distance at what looks like the time of taser deployment would have been about 12 feet, well within taser range. And, he did move after he was on the ground.
It could have been a GSW to the spine, but from the video I am not seeing any evidence of a head or neck wound. Also, the officer to the left of Lavoy is behaving like he is using a taser, and not a pistol. (His right hand is at his hip during deployment of the taser, you can see him stripping wire from the taser as he maneuvers around Lavoy, and he wouldn’t have had a safe shot with a firearm).
We will get a better idea of what happened if/when the coroner’s report is released.