ST. LOUIS — On edge after a night of protests that led to dozens of arrests and a broken window at the mayor’s home, this city faced more demonstrations on Saturday after the acquittal of a white former police officer who shot and killed a black driver.
Tensions here have seemed especially high, in part because the region has been at the center of the nation’s debate over police treatment of black people. St. Louis is about 10 miles south of Ferguson, where unrest erupted three years ago after another police shooting.
City and state law enforcement officials repeatedly struck a note of warning on Saturday, promising that they would not tolerate violence during the protests.
Just after 9 p.m., a two-hour march that had meandered through University City, a St. Louis suburb, came to a peaceful end. However, about two hours later, when the police ordered a group to disperse, some people in the group would not let the officers make it to their vehicles safely and several individuals began throwing bricks and water bottles filled with paint thinner and gasoline, the police said in a statement.
At a news conference earlier Saturday night, Lawrence O’Toole, the city’s acting police chief, said that most of the demonstrations had been peaceful and that officers were committed to allowing peaceful protesters to speak out.
Saturday morning, about 200 people had gathered in a park in University City to march. Joan Bray, 72, a former state lawmaker who was in the crowd, said she was distressed “that the verdict was so inevitable,” adding, “It’s so sided to the police.”
Protesters also converged on West County Center, a suburban mall about 20 miles from St. Louis and chanted, “You can’t stop revolution” and “No justice, no profits.”
A few stores closed their security gates but reopened after the demonstrators had passed. Police officers stood indoors nearby.
The demonstrations continued at various retail sites in the afternoon. Protesters marched through the Chesterfield Mall, another suburban shopping center west of St. Louis, and then to the Taste of St. Louis, an outdoor exhibition for local restaurants.
Mike Kociela, the producer of the Taste of St. Louis, welcomed the marchers. Some protesters were allowed to take the microphone at the bandstand.
“We love you. Whether you love us back is irrelevant,” Cori Bush, 41, an African-American activist from the suburb of Florissant, told the mostly white patrons. “We are not trying to take anyone hostage. We are here to let you know that black lives matter.”
The band U2 canceled a concert scheduled for Saturday night at the Dome at America’s Center in St. Louis because the city’s police department could not provide enough officers for security, a statement on the band’s website said.
“We cannot in good conscience risk our fans’ safety by proceeding with tonight’s concert,” said the statement with Live Nation, the concert promotion company.
Other local events were also canceled or postponed. PeaceFest, which was planned for the campus of Harris-Stowe State University on Saturday, was postponed until Oct. 28, and the university said its campus would be closed until Monday. The St. Louis Symphony canceled a performance scheduled for Saturday, as did the Shakespeare Festival St. Louis. A Sunday evening concert by the pop singer Ed Sheeran was also canceled.
Josh Hawley, the attorney general of Missouri, said in a statement that he expected the authorities to prosecute those who engaged in violence.
After a group called Resist STL posted a video by a television station of police officers pushing an older woman and then stepping over her after she fell, the department tweeted on Saturday that she had “failed to obey officers’ orders” and was charged with “interfering.”
At a news conference on Saturday, Gov. Eric Greitens of Missouri praised the police and warned: “Everybody should be out there making good choices. If you riot, we’re going to cuff you. If you assault a law enforcement officer, we’re going to arrest you.”
He added: “Vandalism is not protest. Vandalism is a crime.”
Members of the National Guard were on standby on Friday night and Saturday, Mr. Greitens said.
Late on Friday, officers gave orders for the crowd to disperse, and used tear gas and pepper balls, the police said, after demonstrators threw bricks and bottles at them.
Some protesters pelted a police bus with rocks, the police said. Thirty-three people were arrested Friday on charges including failure to disperse and interfering.
The authorities said that 11 law enforcement officers from several departments had been injured; none of the injuries were life-threatening.
About 1,000 protesters marched through the streets to the home of Ms. Krewson, where at least one window was shattered after something was thrown at it.
Within minutes, the police ordered protesters to disperse, and a long line of officers in riot gear arrived and marched toward the crowd, pushing protesters away.
This region had been bracing for weeks for the outcome of the trial, in which Jason Stockley, a former St. Louis officer, had been charged with murder in the death of Anthony Lamar Smith, a driver he chased after believing to have observed a drug deal, according to defense lawyers.
Prosecutors, who had waited five years to charge Mr. Stockley in the 2011 shooting, described Mr. Stockley in court as an out-of-control officer who chased Mr. Smith for three miles at speeds of more than 80 miles per hour, shot him for no reason and then planted a .38-caliber revolver in Mr. Smith’s car.
Prosecutors pointed to Mr. Stockley’s remark to his partner, captured on a recording device inside the police car during the chase, as evidence of premeditation: “Going to kill this” person, Mr. Stockley had said, using an expletive, “don’t you know it.”
But Mr. Stockley’s defense lawyers said the officer had acted reasonably in fatally shooting a suspect in a drug deal that the officer had tried to stop before the car chase took place. Defense lawyers have said that the officer believed Mr. Smith was armed, and was reaching for a gun — the weapon that was found in his car after the shooting. Mr. Smith was shot five times.
The case, a bench trial, ended almost a month ago, but Timothy Wilson, a judge with the St. Louis Circuit, issued his verdict on Friday. Judge Wilson said he was “simply not firmly convinced of defendant’s guilt.”
The judge also voiced doubts, in his 30-page ruling, that a gun had been planted on Mr. Smith, writing “that an urban heroin dealer not in possession of a firearm would be an anomaly.”
After the verdict was announced, the St. Louis branch of the N.A.A.C.P. called for the Department of Justice to review the case, The Associated Press reported. But a Department of Justice spokeswoman said the department had looked at the case in 2012 and 2016 and decided not to prosecute.