CHICAGO - A protest march has begun in Chicago's shopping district, with the Rev. Jesse Jackson in the middle of a crowd that's shouting, "What do we want? Justice. When do we want it? Now!"

Several hundred demonstrators have gathered in the drizzling rain, many with umbrellas and plastic-wrapped signs.

Among them is 73-year-old Frank Chapman of Chicago, who says a video released Tuesday showing the fatal shooting of 17-year-old Laquan McDonald by police officer Jason Van Dyke confirms what activists have said for years about Chicago police brutality.

He says his organization, the Chicago Alliance Against Racism and Political Oppression, is pushing for an elected, civilian police accountability council.

A smaller group of protesters, One Chicago, is calling on demonstrators to shut down businesses to protest the city's handling of the investigation. Mark Carter, a One Chicago organizer, is exhorting the crowd to, "Stop watching the show. Shut this down! Shut this down!"

Others are yelling at the police officers lining the route. The officers are not responding.