Cops: Columbine-Style Plot Foiled In Pa.

A home-schooled teenager amassed a cache of guns, knives and explosive devices and tried to recruit another boy for a possible school attack, authorities said Thursday.

The 14-year-old was taken into custody after police searched his bedroom in a Philadelphia suburb Wednesday evening. He had talked about mounting a Columbine-type attack at Plymouth Whitemarsh High School, authorities said.

CBS News correspondent Maggie Rodriguez reports that officials here know the young suspect's motive: He felt bullied by the students at Plymouth Whitemarsh. But the plot for revenge was foiled when the young man tried to seek out an accomplice who led police to the suspect's house and a disturbing arsenal.

The weapons included a 9 mm assault rifle that the teenager's mother had recently bought for him, Montgomery County District Attorney Bruce L. Castor Jr. said. Prosecutors are reviewing her actions.

Police also found about 30 air-powered guns, swords, knives, a bomb-making book, videos of the 1999 Columbine attack in Colorado and violence-filled notebooks, Castor said. The weapons were plainly visible in the boy's bedroom, Castor said.

Also discovered were seven explosive devices Castor described as homemade grenades: plastic containers filled with BBs to which gunpowder could be added. Authorities said one grenade was operable and the others had been in the process of being assembled.

The search did not turn up any ammunition for the most dangerous firearm in the bunch, the assault rifle.

"I do not think an attack was imminent and I am not certain that an attack was going to occur at all," Castor said at a news conference. "It could have simply been big talking by a kid who thought that he was bullied previously and he was going to exact his revenge."

The teen previously attended middle school in the district but had been taught at home for more than a year after voluntarily leaving school, Castor said.

Plymouth Township police searched the home after getting a tip Wednesday from a high school student and his father.

The teen was charged as a juvenile with solicitation to commit terror and other counts and was being held at a youth facility. He was due in court for an initial appearance Friday morning.

A call to the county Public Defender's Office, which was representing the youth, rang unanswered after business hours.

Castor declined to name the suspect's parents and said he did not think they had retained lawyers.

"They are now under investigation by us, concerning whether there's any complicity in putting the weapon in this boy's hands," Castor said.

The arrest came the same day a 14-year-old in Ohio opened fire at his Cleveland high school, wounding four before killing himself.

Classes were held as usual Thursday at the Pennsylvania high school.