Authorities say an 18-year-old American student is behind bars after collecting the supplies needed to bomb his school in South Carolina.
Ryan Schallenberger was arrested on Saturday after his parents called police when 4.5 kg of ammonium nitrate was delivered to their home.
Police Chief Randall Lear said the teen planned to make several bombs. Lear said he had all the supplies needed to kill dozens of people at Chesterfield High.
Lear said a diary Schallenberger kept for more than a year had detailed plans, including maps of the school.