CHICAGO, IL - DECEMBER 18: Demonstrators block a police vehicle that was trying to leave wth people who were taken into custody while participating in a march calling for the resignation of Chicago Mayor Rahm Emanuel on December 18, 2015 in Chicago, Illinois. A recently released video showing the shooting of teenager Laquan McDonald by Chicago Police officer Jason Van Dyke has sparked almost daily protests in the city. Demonstrators have accused Emanuel of trying to cover up the circumstances surrounding the shooting. (Photo by Scott Olson/Getty Images)
