(CNN) -- The teenager accused of seriously injuring students at a Pittsburgh-area high school in a mass stabbing now stands charged with 21 counts of attempted homicide, a Pennsylvania district attorney said Friday.
Previously, 16-year-old Alex Hribal had been charged -- as an adult -- with four counts of attempted homicide and 21 counts of aggravated assault. Westmoreland County District Attorney John Peck told CNN about the updated charges.
The teen allegedly rampaged through the halls of Franklin Regional Senior High School on the morning of April 9, using two kitchen knives to slash those in his path.
The school is in Murrysville, a middle-class enclave with about 20,000 people located roughly 20 miles east of Pittsburgh.