This is an extreme close-up of the SN window in the Powell picture.
I was trying to make sense of the way the boxes that form the Sniper's Nest are arranged. Initially I thought there were two stacks of boxes to the east of the tall stack but now I think there are three stacks.
This means that by the time the Crime Lab came to take it's pictures, the two most easterly stacks of the SN had been removed. The crime scene was basically dismantled before the Crime Lab got to work.
While studying the picture I became confused by the dark area circled. It appears to be an object between the wall of boxes and the camera lens.
Walt has already put forward it is a rifle but it would be good to hear other thoughts: