Unfortunately, given the little that has been publicized about this case, I don't think that this was an accident. If it was an accident there is a slight chance that the guilty party saw what they did and fled the scene rather than reporting it. I think that even if that were the case that they would have eventually turned themselves in, especially after having learned a reward was being offered and knowing therefore, that there would be more pressure on them.
There was a murder a few years ago, I can't remember the state, that was killing hunters and he was eventually caught. This guy ought to keep that in mind if he thinks that shooting someone, even in the woods, is a crime they can get away with.