A community mystery: the murder of Annie Edison

Allison Edison was murdered outside of her apartment twelve days before Christmas, no one around and the only clue? It was someone in the study group. Who was it? What was their motive? Who's innocent? Do they have proof?
Its based around the time troy and britta were dating but doesn't connect to the show I just thought that it was a cool idea.
Also this is my first story so the grammar is probably terrible along with the story but oh well, ya gotta start somewhere, right? :-D