While Cullen points out that Eric’s rants made him, in all likelihood, sound insane to most readers of his journals, Agent Fusilier “ticked off Eric’s personality traits: charming, callous, cunning, manipulative, comically grandiose, and egocentric, with an appalling failure of empathy. It was like reciting the Psychopathy Checklist.” Cullen goes on to add: “Diagnosis didn’t solve the crime, but it laid the foundation. Ten years [after the Columbine shooting], Eric still baffled the public, which insisted on assessing his motives through a ‘normal’ lens. Eric was neither normal nor insane. Psychopathy … represents a third category Psychopathic brains don’t function like those in either of the other groups, but they are consistently similar to one another. Eric killed for two reasons: to demonstrate his superiority and to enjoy it” (239).

Cullen follows with more background on psychopaths and psychopathy, saying that psychopaths have “likely plagued mankind since the beginning, but they are still poorly understood.” They have a duo of distinguishing characters: “The first is a ruthless disregard for others … The second is an astonishing gift for disguising the first” (240). Cullen adds that lying is a signature characteristic of psychopaths, and that symptoms are often reported even prior to kindergarten.