[user104658]

Is there any real suggestion that he dragged the dog deliberately? Story isn't entirely clear on that - though obviously, even if not, his actions on discovering what had happened were negligent at best (i.e. the dog should have been taken straight to a vet).

I'm not watching the video but that article makes it sound like the initial dragging was accidental, and it was the failure to get veterinary attention/attempt to cover it up that's been considered criminal.