(CNN) -- A Pennsylvania teen has been charged as an adult for allegedly planning to kill classmates he did not like before turning the gun on himself in a high school shooting spree, a Pennsylvania prosecutor said Tuesday.
Richard Yanis allegedly stole three handguns from his father and told police he planned to "shoot students in the school and then himself" at Pottstown High School, Montgomery County District Attorney Risa Vetri Ferman said in a press release.
Yanis, 15, was charged with attempted murder in adult court because juvenile law in Montgomery County excludes crimes committed with a deadly weapon, Ferman said.
The investigation began when the teen's father reported that three handguns were stolen from a secured gun locker in his basement, Ferman said.
His son allegedly took a Smith & Wesson .357 caliber revolver, a Smith & Wesson .22 caliber semi-automatic pistol and a Colt .45 caliber semi-automatic pistol, Ferman said.
Richard Yanis gave the guns and ammunition to an unnamed friend from school and asked him to "hold onto it," the statement said. The friend allegedly showed his stepmother the guns, and the two drove to a nearby creek where they tossed in the weapons.
The friend told a teacher at Pottstown High School what happened, and police were called.
Yanis told police he planned to attack the school after the New Year, officials said.
"He was going to go into the school shooting, shoot everyone he did not like, and then himself," Ferman said.
"He was to have the guns loaded and have the additional ammunition inside his backpack," she said. "On the day of the planned shooting, Yanis said he was going to tell his friends to go home from school."
John Armato, director of community relations at Pottstown Senior High School, described Yanis "as quiet, relatively introverted."
"He did not have a great number of friends or a history of discipline problems," Armato said. "He had no history of aggressive behaviors in school."
Yanis' parents had no comment, but family friend Brian Hanlon spoke on their behalf.
"I can say that it was definitely out of character, but that his parents are dealing with it as best as possible," Hanlon said. "They want everyone to respect their privacy at this time while dealing with these events."
CNN's Chloe Melas contributed to this report.
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