Who is Evie Cottrell from Invisible Monsters and what is their importance?

Evie Cottrell is Shannon's best friend before the shooting. Evie and Shannon go to modeling school together and then share many modeling jobs together. Evie is a dramatic person who likes to put her life out where people can see it. Evie enjoys going to a local department store and playing out her life for people to watch. During some of these impromptu dramas, Evie asks Shannon repeatedly about her brother, trying to force Shannon to admit that she does not know for sure that her brother is dead. Shannon never really admits this fact, but Evie continues to push the issue for a reason that is not clear until later in the novel.