A Good Student's 'Unexpected' Bomb Plot

A South Carolina teenager arrested for plotting to bomb his school had designs for an arsenal of explosives including a nail bomb that would have "devastated" students in a crowded hallway, a local police chief said today.

Ryan Schallenberger, 18, called his plot "Columbine III" and laid out details in a "bomb summary" that described the different types of explosives he would use in the suicide attack. He even recorded his expenses.

"I think he was more concerned about a high body count than killing anyone in particular," Chesterfield Police Chief Randall Lear told ABC News.

Schallenberger's "summary" contained details for a nail bomb.

"Inside a school, with confined concrete walls, just a little bit of nails, nuts and bolts, ball bearings and some of these explosives devices, it would devastate the student body," Lear said.

Authorities arrested Schallenberger on Saturday after a package arrived at his family's rural South Carolina home and his parents opened it to find 10 pounds of ammonium nitrate, a substance that can be used as an explosive when combined with diesel fuel or another accelerant.

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The teen's parents called the police, and officers recovered the explosives material and found details of the high school senior's plot. Schallenberger, who was not at home at the time, was picked up along a dirt road near his house.

No guns or other weapons were found in the house.

"I can honestly tell you, were I faced with that scenario, I don't know if I could have made that decision," Lear said. "I don't know whether I would have been brave enough to do what these parents did."

Schallenberger, who had recently won a partial scholarship to college, said nothing and appeared agitated during a brief court appearance today, in which he was assigned a lawyer. The county prosecutor said he will ask that Schallenberger undergo a mental health evaluation.

The bomb summary found in the suspect's bedroom laid out a map of the school, the different types of explosives that would be used in the attack and specific materials needed for each.

While there was no date provided for the bombing, Lear said that with the shipment of ammonium nitrate, he had all the materials he would need to carry out the attack at his fingertips.

"This was a legitimate threat," Lear said. "Once that package was in, he had what he needed to formulate these explosives devices."