When you look at the Zodiacs age, if we take one age proposed that he was in his mid twenties in 69, then present day he would be poss late sixties, coming up for seventy. How many guys even in this age range go out hunting in all conditions, I would bet there is quite a few. And in 2004 he would have been early sixties at least. I think it's entirely possible if still alive that he could have been committing crimes. All he required was the ability to get around, aim and fire a gun.