Updated at 8:12 a.m. ET
A 10th-grader suspected of committing a stabbing rampage at a Pennsylvania high school on Wednesday has been charged as an adult with four counts of attempted homicide and 21 other counts.
The suspect, identified as 16-year-old sophomore Alex Hribal, injured at least 22 people before being taken into custody, the Associated Press reports. The teenager reportedly had a "blank expression" on his face as he slashed at his victims. He was being held without bail Thursday in a juvenile detention center.
Many of the victims—at least 21 students and a security guard—were critically wounded and hospitalized, though there were conflicting reports about how many. No deaths had been reported by Thursday morning. Several of the victims from the Franklin Regional High School outside Pittsburgh suffered life-threatening injuries, health officials said, but all were expected to survive. Eight patients were transported to nearby Forbes Hospital, including three male students between 15- and 17-years-old who suffered relatively deep single stab wounds with a wide knife. One of the three was in stable condition while the two others the hospital described as "critical but stable."
"It was penetrating enough to damage multiple organs," Chief Medical Officer Dr. Mark Rubino said. Four more male students at the facility suffered superficial injuries and one 60-year-old adult was treated for a non-stabbing medical issue and released.
Police said the suspect used kitchen-style knives between eight and 10 inches long in the attack. A motive for the attack at the school, about 18 miles east of Pittsburgh in Murrysville, was not yet known. Officials said the student brought two knives into the school. Mark Drear, the vice president of a security company with personnel at the school, said on CNN that the suspect "was just running down the hall stabbing kids as they were going by."
One student described Hribal as introverted, but claimed she was unaware of him exhibiting violent tendencies in the past.
"He didn't talk to many people," Mia Meixner, a sophomore, told USA TODAY. "He wasn't mean or anything, he just wasn't outgoing."
Police said the school's principal tackled the suspect and helped with the arrest, along with security guards on the premises. The stabbing took place in several classrooms and hallways as the school day began.
"I was shocked and saddened upon learning of the events that occurred this morning as students arrived at Franklin Regional High School," Pennsylvania Gov. Tom Corbett said in a statement. "As a parent and grandparent, I can think of nothing more distressing than senseless violence against children. My heart and prayers go out to all the victims and their families.”
Victims were being treated for stab wounds to their torso, abdomen, chest and back areas. Three medical helicopters and dozens of ambulances were dispatched to the scene, the local CBS affiliate reports. The stabbings occurred in the science wing of the school building at 7:13 a.m., people on the scene said, and lasted for about 15 minutes before the student was apprehended.
Franklin Regional school district canceled all elementary classes.