The Knox family probably did some well placed bribing,,and combined it with a professional PR campaign. Literally hiring a PR firm.
It was basically aquittal by news media.
Everyone misses the point. I doubt she set out to kill her. Probably just tried to make her have sex with that African dude. According to the other roomates, she was accusing Meredith of being a racist for not doing him. I think they tried to force something, hoping she would get into it. (as was a theme in one of Amandas short stories)
But the girl fought and screamed, they shut her up. And then they had a dead roomate and one big problem. SO they came up with those sophomoric alibis.
My opinion is that you are probably closest to the truth. Just my opinion though based upon what I read and heard.
Lol, you are aware that Meredith was part black, right ?