The first step is to see if we can figure out her name. Who do we know who might have seen her around when she was alive?
Hint 2
Joey recognized her from the picture of JoAnn, so maybe she was a student. Maybe JoAnn's roommate could help.
Hint 3
Go back to see Kelly (with Joey), and this time she lets you into her room. Look at the pictures on the bulletin board at right to find photos of all three girls in the photo you already have --
Hint 4
-- but they don't have complete names. Ask Kelly about Alli and Susan to learn something more, but not enough.