Crime Scene Case!!!!!!!!!!!!!!!!!!!!!!?

So I'm doing a "crime scene investigation" (faaaaaaake one everybody) for homework. It's called "The Case of Lois McArthur." I know that some of you probably got igned the same thing....... It's famous xD Anywho... Who killed Lios? Was it Maria? Her best friend? BUT SHE WASN'T WEARING ANY COTTON! (At the crime scene, there were cotton fibers found, and they weren't Lois's.) So who was her accomplice? Or just, who do you think did it? (For those of you who have done this "case" before) THANK YOU AND 10 POINTS TO THE MOST REASONABLE... :D