That is the part I just do not understand (dragging her body to be parallel with Abby's). For what purpose? There had to be a purpose in the killer(s) mind(s). Otherwise, why not just leave her where she dropped to the ground? Why not drag Abby, who would have been easier to drag, over by Libby? Just why not leave them where they died?! I can't wrap my head around their reasoning.
IMO not wanting to disturb Abby‘s body.