Not that I can even pretend to know diddly after what happened to me this year, but we marked every speck of blood we found with sticks and the next day when I went back to look again it gave me a clearer visual picture of what the deer might have been thinking. (I'm sure that toilet paper or marking tape would work better, but that is all we had at the time) It didn't help me recover my deer, but maybe it will help you somehow.

Believe me, I know your anguish over this!