(CNN) -- Police have taken into custody a 14-year-old boy who is suspected of planning a "Columbine" type event at a Pennsylvania high school, a police spokesman said.
Police took a 14-year-old boy into custody after a search of his home turned up dozens of weapons.
Police in Plymouth Township near Philadelphia took the boy into custody after a search of his home turned up a number of weapons, including a 9 mm rifle with a laser scope and dozens of air guns, said Deputy Chief Joe Lawrence.
Police also found an operational hand grenade, three other hand grenades in the process of construction, bomb-making equipment, manuals and 30 powered weapons that fire BBs.
The boy's mother bought the rifle for him several weeks ago at a gun show, police said. No ammunition was found for the rifle.
The grenades were made with plastic casings that authorities believe the boy bought on the Internet, Lawrence said. The operational hand grenades included black powder, BBs and a fuse believed used in fireworks.
Lawrence said police are also investigating whether the boy's mother bought him black powder used in the grenades.
The boy was making the grenades in his bedroom, he said.
In addition to the weapons, authorities found a hand-painted Nazi flag and a video about the Columbine shootings, District Attorney Bruce Castor said. Watch Castor explain why he is 'very upset' with the parents »
"It is my judgment that this individual considered that something to be glorified and was doing so," he said.
Two students opened fire at Columbine High School in Littleton, Colorado, on April 20, 1999. They killed 13 people and wounded 23 others before killing themselves.
The 14-year-old is expected to appear in juvenile court Friday to face charges that could include making terroristic threats, criminal solicitation, weapons possession, and possession and manufacturing of weapons of mass destruction, police said.
If he's found delinquent, he could face jail time and counseling.
The boy's mother and father may face criminal charges pending an investigation, police said.
"I don't see any evidence that leads me to conclude that she knew that this attack was planned or anything of that nature," Castor told "Anderson Cooper 360."
But he said he thinks charges against the mother are likely. "I think you have a parent who has fallen down on the job in supervising the child, perhaps indulgent on the child because she knows he has issues."
Police acted on a tip they received at 7:30 p.m. Wednesday from a Plymouth Whitemarsh High School student and his father, school officials said. The 14-year-old was taken into custody at his home about 10 p.m.
"The boy who gave the tip was one who was trying to be recruited," Castor added. "He was a friend of the boy in the loosest terms."
Officials said they think the tip was prompted by Wednesday's shooting at a school in Cleveland, Ohio.
"We have no information at this point that leads us to think this is other than an isolated individual who was trying to recruit others to help," Castor said.
School officials said the boy is not a student at the school.
"This was a youth in the community who has not been enrolled in school since spring of 2006," according to Dave Sherman, spokesman for Plymouth Whitemarsh High School.
The school has an enrollment of 1,591 students in grades nine through 12. No classes are being canceled because of the incident, school officials said Thursday.
Plymouth Township is about 15 miles northwest of Philadelphia. E-mail to a friend
CNN's Caleb Silver, Catherine Clifford and Diana Miller contributed to this report.