Last Updated Apr 9, 2014 9:30 PM EDT
MURRYSVILLE, Pa. - The 16-year-old suspect in a bloody stabbing spree at Pennsylvania high school seemed to be a shy, quiet boy who largely kept to himself, schoolmates said.
Police say the suspect, armed with two knives, stabbed and slashed more than 20 students and a school security officer on Wednesday morning at Franklin Regional High School in Murrysville, an upper-middle suburb area 15 miles east of Pittsburgh.
Authorities said the rampage ended when an assistant principal tackled the assailant, identified as Alex Hribel.
Hribel was treated for a minor hand wound, CBS Pittsbugh said. Wearing a hospital gown and shackled by his hands and feet, the slight teenager was taken from the Murrysville police station Wednesday afternoon to appear before a magistrate.
He was charged with four counts of attempted homicide and 21 counts of aggravated assault. He was ordered held without bail and authorities said he would be prosecuted as an adult.
Hribel was a sophomore at Franklin Regional, where he didn't especially stand out. Schoolmates said he was quiet but not an outcast.
"He was never mean to anyone, and I never saw people be mean to him," said 16-year-old Mia Meixner, who was not hurt herself but said she saw other students being stabbed. "I never saw him with a particular group of friends."
She said she didn't know Hribel very well.
"I think he just kept to himself. He was quiet, just didn't really care what other people did," she said.
Witnesses said the teen had a "blank expression" on his face as he jabbed at student with the knives. Nate Moore, 15, said he saw the suspect tackle and stab a freshman before the attacker got up and slashed Moore's face.
The attacker "had the same expression on his face that he has every day, which was the freakiest part," said Moore, who required 11 stitches to close his wounds.
"He wasn't saying anything. He didn't have any anger on his face. It was just a blank expression."
Meixner said the suspect had a "blank look" during the rampage.
"He was just kind of looking like he always does, not smiling, not scowling or frowning," she said.Hribel lives in a colonial home on Sunflower Court in Murrysville with his parents and a brother who is a junior at the high school, CBS Pittsburgh said. Police were keeping reporters at a distance from the house on Wednesday evening as investigators searched the boy's computers.
Neighbors said they were stunned by the boy's arrest in the rampage.
"I'm just in shock," neighbor Lori Renda told the station. "I have no idea what could have caused it at all."
"We've known them since we moved in. It's tragic," said Terri Ledonne, another neighbor.