A home-schooled teenager who amassed a cache of weapons, including a hand grenade, and tried to recruit another boy for a possible school attack in Pennsylvania was charged with solicitation to commit terror, authorities said Thursday.

The 14-year-old, who authorities said had felt bullied, was taken into custody after police raided his home in the Philadelphia suburbs on Wednesday evening. He had talked about mounting an attack on Plymouth Whitemarsh High School similar to the 1999 massacre at Colorado's Columbine High School, authorities said. In that incident, two disgruntled teens killed 12 classmates and a teacher before killing themselves.

"I do not think an attack was imminent and I am not certain that an attack was going to occur at all," District Attorney Bruce L. Castor Jr. 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 was charged as a juvenile with solicitation to commit terror and other counts and was being held at a youth facility. It was not immediately clear if he had a lawyer.

The arrest came the same day that another teenager shot and wounded four people at an alternative high school in Cleveland, Ohio, before killing himself. Students at SuccessTech said Thursday their warnings that the 14-year-old boy was planning such an assault went unheeded by the school's principal.

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 weapons found included a 9 mm assault rifle that the teenager's mother had recently bought for him, Castor said. Police also found about 30 air-powered guns, plus swords, knives, hand grenades, a bomb-making book, videos of the 1999 Columbine attack in Colorado and violence-filled notebooks. The weapons were plainly visible in the boy's bedroom, Castor said.

They found no ammunition for the most dangerous weapon, the assault rifle.

Plymouth Township police say they received permission from the boy's parents to search their home after getting a tip Wednesday from a high school student and his father.

Authorities also found one working hand grenade and three others that were still being assembled.

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