CLARA The Stolen Identity

Clara was deceived by her envious friend and raped and murdered by her wicked peers; they didn't expect to see her at school alive and unharmed.

Once Clara's perverted classmates and her traitor friend discovered the truth, Clara began acting extremely creepy and made their lives miserable. Is the Clara they are seeing the real Clara or is she just a person posing as Clara? If so, why is she doing this? Is she looking to exact justice on Clara? Unless, why?