I dunno. I doubt anyone here can. Sometimes you can guess on bubbles, non red colors, how bright of red. I am not a pro, just read stuff.
I give you credit tracking so far. I think you need to keep looking for blood, or just circle area. Though I have not had luck with that.
if you can't find blood, my guess is circle area of last spot. If he was going straight line, could keep going straight. When I have seen them turn, it was right away. But that may not be a rule. T
I kinda doubt you can guess looking at map. But I am guessing.