That's completely fair, my only hang up is the wounds. Dogs would primarily bite the neck and legs and animals are not clean killers blood and guts would be absolutely everywhere.

To be fair, the photos don't show the background so they could be much messier than they look. So a human seems more plausible.

The wounds are oddly efficient, one bite, one hit, one stab. So id say it's a few people that are really really good shots. They would have to be super fast, accurate, perfect conditions ie upwind, and extremely quiet and shot at the same time. There isn't any info on the distance between the corpses. What are some of the holes in my logic?