They did stage some aspects of the sexual assault, we don't know exactly what really happened that night.
Some staging of things was involved. This means that evidence was distorted. Thus, by necessity from those two acts, we do not have a clear picture of the what is real evidence and what is fake evidence.
So therefore how can we base our conclusions about this case from strictly taking the "evidence" we see, since we already know evidence has been changed by the perpetrators?
For example, the broken window - if investigators had not looked "beyond" the outward appeance of the broken window, and just taken it immediately as fact, then they would not have known the window was staged.
It is a very, very strange case indeed.