Okay, thanks for the clarification. It'll be hard to point out to you without drawing a circle to where I see it. It's at a distance and almost camouflaged perfectly within the trees. In the image discussion thread, they have it circled and have cleaned up the image so you can view it more easily.
So keeping in mind that it is difficult to make out without drawing upon the image, people claim that they see him coming from the direction of the crime scene which would be to the right of the bridge, but slightly to the left of Abby, close to the platform. (This is from Libby's vantage point)
Oddly, he (if that is what it is) is more centered in Libby's picture, than what Abby is. Based on that, I wonder if Libby caught his movement walking through the trees, heading toward the end of the bridge, and this was when she started to get uncomfortable. Or it could have been intended to be an "artistic" photo of Abby upon the bridge, and he was subsequently caught in the photo.
I think that within the short timetable from this particular photo (about midway across the bridge, just past the water), that it could likely be him considering by the time they saw him, they were on the other side and he was fairly close to them at that point.
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