School stabbing: 16-year-old charged as adult, 22 hurt at Pa. high school

      |Alex Hribal, 16, was charged as an adult with four counts of attempted homicide and 21 counts of aggravated assault. Hribal injured 21 students and a security guard before being tackled and immobilized by faculty and students. CBS News' Vinita Nair reports on the investigation into a motive.

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