US school stabbing suspect had 'blank expression on his face'

It was just before the start of class and the hallways were packed with students at their lockers or chatting with friends.

Nate Moore was walking to class, book in hand, when a classmate he knew to be quiet and unassuming tackled a first-year boy a few metres in front of him. Moore thought it was the start of a fistfight and went to break it up.

But 16-year-old Alex Hribal wasn’t throwing punches — he was stabbing his victim in the belly, Moore said. The suspect got up and slashed Moore’s face, then took off down the hall, where authorities said he stabbed and slashed other students in an attack that injured 21 students and a security guard. It might have been even worse but for the “heroes” who Pennsylvania’s governor said helped prevent further injury or loss of life.