I think that when searchers initially found the girls, it was not evident at first glance that a crime had happened. Also, if the searchers thought they were looking for girls who had been out in the cold all night, your brain will try to fit what you see into that scenario. You might not be able to process what you actually see, if your brain is fixed on another scenario. I agree that it could not have been a very bloody crime scene. I think the girls might just have been lying there as if they we sleeping, and only at close examination you would discover that a crime had happened. I think this is part of the signatures. Maybe it was a violent crime, but after the fact the killer spend time to make it look like something else. Maybe this is also why the crime scene is referred to as “odd”, because with what had happened to the girls, how they were killed, you would expect the crime scene to look different?