A 17-year-old boy described as a "good kid" by school officials had been secretly planning for almost a year to make his high school the next Columbine or Sandy Hook, authorities say. Police say John David LaDue plotted to kill his family before setting off pressure-cooker bombs in Waseca Junior/Senior High School and gunning down any surviving students, the Mankato Free Press reports. His plans—and his idolization of the Columbine killers—were detailed in a 180-page notebook police found after his arrest earlier this week.
Authorities say LaDue "was fully prepared and ready to go" and the attack would probably have taken place within weeks if police hadn't been tipped off by someone who called 911 after seeing the teen behave suspiciously at a storage unit, reports the New York Daily News. Inside the unit, the bomb squad found what they described as the largest amount of bomb-making material they had seen in their careers. In his bedroom, police found an assault rifle with 400 rounds of ammunition and several other firearms. The teen, who admitted setting off several bombs around town as he prepared for the massacre, has been moved to the state's most secure juvenile facility after threatening to kill workers at the facility he was first sent to, reports the Minneapolis Star Tribune. (Read more school shooting stories.)