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.