Michele Cossey bought her home-schooled son a .22-caliber handgun, a .22-caliber rifle and a 9 mm semiautomatic rifle, authorities said.
CBS News correspondent Maggie Rodriguez reported that officials knew 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.
Acting on a tip from a high school student and his father,, about 30 air-powered guns, swords, knives, a bomb-making book, videos of the 1999 Columbine attack in Colorado and violence-filled notebooks in the boy's bedroom, Montgomery County District Attorney Bruce L. Castor Jr. said.
Cossey, 46, of Plymouth Meeting, bought the rifle, which had a laser scope, at a gun show Sept. 23 and provided police with a receipt, investigators said in court papers. The teenager said the two .22-caliber weapons were stored at a friend's house.
The teen was ordered Friday to remain in juvenile detention.
His mother was charged with unlawful transfer of a firearm, possession of a firearm by a minor, corruption of a minor, endangering the welfare of a child and two counts of reckless endangerment. She was later released on bail.
Castor has said he does not believe and attack was imminent nor would occur at all. He said Friday that the teen had a "disturbed mind."
"This was a smart kid that clearly believes he was picked on and was a victim," Castor said. "He had psychological issues and began to act out on those feelings."
Suspect's MySpace Page Alluded To Columbine
On his MySpace page, the 14-year-old boy accused of planning an attack on a high school makes frequent references to Eric Harris and Dylan Klebold, and describes their 1999 massacre at Columbine High School as one of his interests.
On his page, headlined with the phrase "Mess with the best, Die like the rest," are tribute videos to the Columbine shooters, and a still from the surveillance video showing Klebold and Harris in the Columbine cafeteria.
In his lone blog post, dated March 29, he wrote about recruiting for his "military group" and about his favorite weapons.
In a badly spelled post, he called himself a soldier and wrote that if he could travel back in time he "would love to be in all the wars, expecialy ww2."
The teen listed "the COLUMBINE MASSACRE" and the North Hollywood Shootout, a confrontation between a pair of heavily armed bank robbers and police in 1997, as among his "fav historical times."
"O and as 4 my personal saying....if at first you dont sucseed, use the armor piercing rounds," he also wrote.
Police, who searched the home with the permission of the teen's parents, also discovered seven explosive devices Castor has described as homemade grenades: plastic containers filled with pellets 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.
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.
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.