Dr. Morrison says Holmes' main reason for revenge was due to his failure in school

Dr. Helen Morrison says, Holmes "does fit the profile of an individual who becomes a mass murderer, meaning that he plans, he implements and the victims are usually individuals that he doesn't know but he's just chosen because of his anger and sense of revenge because of his rejections.”

Dr. Morrison goes on to say that Holmes' main reason for revenge was because he "was not making it in the doctoral program in neuroscience."

The graduate student dropped out of school in June.