BATON ROUGE, LA. On the affluent south side of Baton Rouge, a clutch of plastic balloons bobs in front of the gas station where a former Marine shot and killed three police officers last Sunday.

On the impoverished north

side of the city, a pile of flowers and a spraypainted portrait mark the spot where resident Alton Sterling was killed by police two weeks ago. Mr. Sterling’s funeral services July 15 drew hundreds of mourners, with the exception of Baton Rouge Mayor Kip Holden.

The impromptu shrines in Louisiana’s state capital illustrate the heartache on both sides of a confrontation over police use of lethal force against mostly African-American men and tareted killings in Dallas and Baton Rouge by African-American gunmen bearing racial grievances against white officers. The differences between law enforcement and activists who have protested a series of police-involved shootings across the United States in the past two years seemed briefly to have been set aside in Baton Rouge in the immediate aftermath of last Sunday’s murders that officials

described as assassinations. Public safety officials and civil rights leaders denounced the killer, identified as 29-year- old Gavin Long of Kansas City, Mo., as a visitor without ties to Baton Rouge who came to their

city with intent to do harm. Two of the officers killed were from the Baton Rouge Police Department. They were identified as Montrell Jackson, 32, a 10-year veteran, and Mat- thew Gerald, 41, who had been serving for less than a year, officials said. Also killed was Brad Garafola, 45, a 24-year veteran of the East Baton Rouge Sheriff’s

Office, officials said.

Officer Jackson is African-American; his funeral will take place 11 a.m. July 25 at Living Faith Christian Center in Baton Rouge. Officer Gerald and Of- ficer Garafola are white. Officer Gerald’s funeral will be 11 a.m. July 22 at Healing Place Church in Baton Rouge, while Officer Garafola’s funeral will be 2 p.m. July 23 at Istrouma Baptist Church in Baton Rouge.

“People on all sides, people who were peacefully protest- ing the Sterling incident, are just as heartbroken over this as everyone in the law enforcement community,” said Louisiana State Representative Barry Ivey, a Republican who represents Baton Rouge.

But some African-American residents worried the ambush could shift attention away from Mr. Sterling’s July 5 death, which many saw as just the latest example of heavy-handed policing.

“How many more innocent people have to be killed before they bring those two officers to justice?” asked Quenton Williams, who described his

own struggles with the court system as visitors took photos and laid flowers in front of the convenience store where Mr. Sterling was killed.

Civil rights leaders said they would continue to press for police reforms, even as they urged frustrated residents to refrain from street protests.

“Just getting a crowd begets tension in and of itself,” said the Rev. Lee Wesley, a leader of the interfaith group Together Baton Rouge.

The Baton Rouge Police Department faces a federal investigation over Mr. Sterling’s death, and is still operating under a decades-old agreement with the federal government to hire more black officers.

Residents said their city had been returning to normal before the killing of the officers.

The protests following Mr. Sterling’s death had petered out and police had not made any arrests for reasons of civil unrest for six days, officials said.

But even as Sunday’s killings prompted an outpouring of goodwill from locals determined to try to use it to soothe long- standing racial tensions, there were signs it may have hardened others’ positions in the debate over police conduct.

An emotional Baton Rouge Police Chief Carl Dabadie said the military-style tactics that are criticized by activists made it possible for Mr. Long to be shot dead from 100 yards away before he could kill more police officers.

“We are up against a force that is not playing by the rules. They didn’t play by the rules in Dallas, they didn’t play by the rules here,” Chief Dabadie said.

In Dallas on July 7, five police officers were killed near the scene of a peaceful demonstration by a former U.S. Army reservist, Micah Xavier Johnson.

Maxine Crump, executive director of Dialogue on Race Louisiana, said that since Sunday’s attack she has been “inundated” with offers from people wanting to be part of discussions on how to improve race relations.

“I do not think this has set us back,” Ms. Crump said.

Some believe progress is unlikely to be made anytime soon.

“We won’t heal this in a week or a month,” said Louisiana state Sen. Mack “Bodi” White.