Activists, clergy members, and family members of Anthony Lamar Smith say they plan mass disruptions in the St. Louis area if Stockley is found not guilty in Smith's killing.
Protesters say they will shut down the airport, a Cardinals game, the downtown area, and other targets if Stockley is not convicted.
The protesters were joined by clergy at the rally on the steps of the Carnahan Courthouse.
Smith was fatally shot by Stockley after a police chase in December 2011. Prosecutors allege Stockley planted a handgun in Smith's car after shooting him five times.
The bench trial for Stockley ended on August 9, but St. Louis Circuit Judge Timothy Wilson has yet to issue his verdict
Organizers say they’re planning at least two more rallies this week calling for the judge in the Stockley trial to return a guilty verdict.