CHICAGO, ILLINOIS—A planned NAACP press conference at Chicago’s City Hall was briefly scuttled by an angry black protester who slammed establishment Democrat activists and members of President Barack Obama’s fractious progressive and multicultural coalition.

The midday demonstration exposed the widespread anger and fractures in Democrat-run Chicago after officials finally released the videotaped shooting of 17-year-old Laquan McDonald in October 2014. The video’s release came as police finally arrested officer Jason Van Dyke for the shooting.

The city is reaching a boiling point after days of “Black Lives Matter” demonstrations last week that culminated in the shutdown of the shopping mecca on Michigan Avenue on Black Friday.

Here’s what the Chicago media isn’t telling people: As shown in a recent interview Breitbart News did with another grassroots black activist, there’s a deep rift that divides many black citizens who want to see Mayor Rahm Emanuel held responsible for what they see as the year-long cover-up of the McDonald shooting, from the establishment Democratic activists—including the NAACP—who have not yet called for the mayor to resign.

On Monday at midday, those leaders staged a protest, during which 10 leaders of the local NAACP were arrested in a staid process.

But just before the NAACP leaders were scheduled to speak, before the arrests, a man named George—Breitbart News was unable to get his last name—grabbed the spotlight and let the Democratic machine have it with both barrels.

George called for Rahm to step down and began calling out establishment fixtures like Rev. Jesse Jackson, Al Sharpton, and Father Michael Pfleger. As Chicago’s media looked on, George called black police officers the “n-word” and became more and more furious.

As George grew angrier and knocked the establishment Democrats off their script, event organizers declined to challenge him. They dropped their plans for a press conference at noon and began their march before the planned arrests.

But a number of grassroots activists in the crowd sided with George’s claim that the Democrat establishment had sold black voters out.

The NAACP protest, complete with professionally-printed signs and half a dozen coffins, did a slow march and chant around City Hall. At one point, protesters moved into the street and ten were arrested, including the local NAACP president Cornell Brooks.

The NAACP arrests were posted on Twitter:

During their rescheduled press conference, the NAACP did not call on Rahm Emanuel to resign.

The rift between established activists and the angry protesters cannot be hidden. As it widens, it may drop Chicago—a city already on the edge of chaos—over the edge.

Follow Breitbart News investigative reporter and Citizen Journalism School founder Lee Stranahan on Twitter at @Stranahan.