Minnesota. Next here, inside a foiled plot to attack a high school. Tonight, a student in his own words lays his plan. So, what led him to the darkest thoughts. Here's Mara schi a, vocampo. Reporter:... See More
Minnesota. Next here, inside a foiled plot to attack a high school. Tonight, a student in his own words lays his plan. So, what led him to the darkest thoughts. Here's Mara schi a, vocampo. Reporter: In never before heard police interrogation tapes, he calmly details a planned high school massacre. My plan was to entire to throw molotov cocktails. Reporter: He told police that he wanted to kill his parents and sister. I was planning to dispose of my family, too. Why would you dispose of your family? What -- what have they done? They did nothing wrong. Reporter: The Minnesota teen says he hid his violent fantasies from everyone, including his father. He thinks I'm just a good kid, because I can lie pretty well and persuade him that I'm just ordinary. Reporter: He said that he was stock piling weapons. And testing homemade explosives. He's pleaded not guilty to charges of attempted murder. In his chilling interview with police, he said that he was never bullied and point to just one reason for his plot. I have good parents, I live in a good town. I think I'm just really mentally ill and no one's noticed. Reporter: He was arrested in April when a neighbor saw him headed to the weapons storeroom and called police. Experts we spoke with, struck by his calm demean your. So caland so collective. You know, it raises questions about anti-social personality features. Reporter: A personality where we're now learning more about. And from a foiled plot to the intense man hunt for an
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