St. Paul police estimated over 2,000 people attended the protest march, which was overall peaceful.
After the verdict was announced, the city of St. Anthony in Minnesota announced that Yanez would no longer be employed as a police officer in the locality.
During a traffic stop last July, with his hands raised, Philando Castille told the officer he had a gun with a permit, but the officer continued to pull out his gun and fatally shot Castille.
During the trial, Yanez testified that Castile was pulling out his gun from his pocket despite his commands not to do so.
For their part, Yanez's lawyers praised the results and said there shouldn't have been charges in the first place.
The shooting death of Castile, 32, triggered local protests and fuelled debate across the USA over the appropriate use of force by law enforcement against minorities. "This time we had to get it right", she said.
The trial of officer Jeronimo Yanez
A Minnesota jury is weighing the fate of a police officer charged with manslaughter in the shooting last July of a black motorist. He also cited testimony from first responders who saw Castile's gun in his pocket as he was loaded onto a backboard.
Minnesota State Patrol officers arrest protesters during a gathering after the verdict.
Indeed, police discrimination against people of color, often under cover of the war on drugs, has been well documented - Mr. Castile had been pulled over, usually for minor traffic infractions, 49 times in 13 years.
Taylor, whose four-year-old daughter was in the backseat, said Castile told the officer: "Sir, I have to tell you, I do have a firearm on me". "I believe that, working together, we can make the changes necessary to secure both safety and justice, in all of our communities, for all Minnesotans", Dayton said in the statement. And, as in prior cases of Black men being shot and killed, the Justice Department could open an investigation into the case, as Castile's uncle has requested.
The event was initially planned to be a Father's Day celebration, but that changed when the officer was acquitted of manslaughter in Castile's death, according to organizers.
The squad auto video shows Yanez approaching Castile's vehicle and asking for a driver's license and proof of insurance. Therefore, Friday night's large-scale protests in St. Paul were expected in the wake of the verdict.
The incident, one of several deaths of black men and boys shot by U.S. police, sparked outrage and protests in St Paul.
She says those arrested were booked at Ramsey County Jail on charges including being a pedestrian on the busy freeway.
People took to Twitter to express outrage over Friday's acquittal verdict in the fatal shooting of black man Philando Castile in Minnesota. Addressing a crowd who gathered outside the courtroom, she added, "My son loved this city and this city killed my son". He says the jury sympathizes with Castile's family.