Calling out for help by capturing police shootings on camera

Why did an officer use lethal force against Philando Castile during a routine traffic stop in Minnesota? Hari Sreenivasan talks to Jelani Cobb of The New Yorker, David Klinger of the University of Missouri-St. Louis and Issie Lapowsky of Wired about the growing impact of social media in police confrontations, police training in implicit bias and whether these videos are changing the conversation.