A day after a video captured white officers pinning down and shooting a black man outside a convenience store in Baton Rouge, Louisiana, federal authorities are investigating the case. Alton Sterling, 37, is dead. The U.S. Justice Department's Civil Rights Division is leading an investigation into what happened. And the president of the NAACP's local branch is calling for the city's police chief and mayor to resign. Tensions are running high as officials vow to be transparent about how they handle the controversial case.