In the wake of the incident , Ulster County investigators searched Bonelli 's room at the home he shared with his father , and found what Ulster County District Attorney Donald Williams described as " Columbine memorabilia " . Officials described the young man as being fascinated by the Columbine High School massacre . Additional searches were conducted by police after videos seized at Bonelli 's residence showed him exploding homemade pipe bombs with a man named Kenneth Stine and another individual . Both individuals were later arrested and charged with violating federal explosives laws
Columbine High School massacre
Columbine High School massacre
Hudson Valley Mall