I've added yellow and blue lines to the image posted by Caroline. As you can see, the bloodspots on the carpet are in the same position in relation to these lines, but Sheila's legs are quite differently positioned in relation to them. The differences are far too great to be entirely accounted for by a difference in camera position. This shows that Sheila's legs have moved several inches inbetween the times when the photographs were taken. Who moved her legs and why?