A community that was barely keeping its anger in check got the first step it demanded on Friday when the Dallas-area police officer who shot dead a 15-year-old boy was charged with murder.

Now, on Saturday, Balch Springs will mourn Jordan Edwards at his funeral, a week after he became the latest black person killed by law enforcement when Roy Oliver fired into a car that was moving away.

“Although this does not take away the excruciating pain caused by the loss of a son, brother and friend,” an attorney for the Edwards family, Lee Merritt, said in a statement, “the announcement that the appropriate warrant has been issued for the arrest of Roy Oliver on the charge of murder has brought a bit of reprieve in a time of intense mourning.

“Although we realise that there remain significant obstacles ahead on the road to justice, this action brings hope that the justice system will bend against the overwhelming weight of our frustration.”

Oliver later turned himself in, and was released after posting $300,000 bond.

Jordan Edwards and his father, Odell Edwards. Photograph: Courtesy of the Edwards family/AP

Criminal prosecutions of officers who kill are rare, and convictions rarer still. But the decision in Dallas to pursue a murder charge will encourage activists as they increasingly look to local authorities to effect fundamental changes in departments’ culture, training and actions.

In February the new US attorney general, Jeff Sessions, said the Department of Justice would “pull back” on legal action against police departments suspected of civil rights violations. Activists are not expecting much interest from the federal government in future police misconduct cases.

There were demonstrations in Baton Rouge this week after it was revealed that two white officers would not be federally charged in the fatal shooting of a black man, Alton Sterling, which happened last July. They may still face action from Louisiana authorities. But in South Carolina on Tuesday a former officer, Michael Slager, pleaded guilty to violating the civil rights of Walter Scott, a black motorist who was running away from a traffic stop when Slager shot him dead in 2015.

“Given the way the laws are set up in our country, it’s always better for the prosecution to happen locally,” said Rashad Robinson, executive director of Color of Change, a civil rights group.

“The widest set of tools exists at the local level. In fact the federal government has very limited tools in terms of stepping in and the bar that is set for federal intervention is very high regardless of who’s leading the Department of Justice.

“But now that we have a Department of Justice that is not only unsympathetic to the safety and justice for communities of colour but is openly hostile to communities of colour, we know that it’s going to be quite hard to see that type of justice.”

The Dallas County district attorney is Faith Johnson, a Republican who became the first African American woman to serve as the county DA when she was appointed by Texas governor Greg Abbott in December. She previously worked in private practice, as a judge and as a felony prosecutor in Dallas.

The charge came six days after Jordan’s death. Last year, when Tulsa police officer Betty Shelby shot dead an unarmed man, Terence Crutcher, she was charged with manslaughter six days later. Her trial begins next week.

About 200 people attended a vigil on Thursday in a Balch Springs park next to the scene of the shooting, where low-slung houses sit on streets named for royal and noble ranks, birds tweet loudly to be heard above the drone of the adjacent freeway and road signs implore: “Please drive slowly, we love our children.”

The crowd held candles as faith leaders spoke and outrage simmered beneath the surface of the sombre occasion.

“We don’t want him indicted for the least possible crime,” Sara Mokuria, co-founder of a Dallas activist group, Mothers Against Police Brutality, told them. “We want him indicted for murder because that’s what he did.”

Jordan James, a 20-year-old student from the area, was among the attendees. “As an African American male,” he said, “I feel like that could have been one of my little brothers, my little cousin, and it hits home for me as I read the details about a little kid getting shot in the head with a rifle.”

Balch Springs police said they responded at about 11pm last Saturday to reports of underage drinking and heard gunshots, and an officer then opened fire as a vehicle supposedly backed towards police “in an aggressive manner”.

On Monday, after viewing body camera footage that has not so far been publicly released, the police chief, Jonathan Haber, said at a press conference the vehicle was in fact moving away.

Merritt told reporters that the five unarmed teenagers in the car – including Jordan’s two brothers – decided to leave a party after hearing the shots. Jordan, a high school student, was in the front passenger seat. Despite federal guidelines advising police not to shoot at moving vehicles, Oliver fired with a rifle and Jordan was hit in the head.

The family called for Oliver to be arrested for murder and claimed in a statement that other officers “manhandled, intimidated and arrested” the car’s occupants while Jordan was dying.

Odell Edwards wipes away tears as he sits with his wife, Charmaine Edwards, in a law office in Dallas on Monday. Photograph: Guy Reynolds/AP

The Dallas County sheriff’s office said in a statement on Friday that the arrest warrant was issued as a result of “evidence that suggested Mr Oliver intended to cause serious bodily injury and commit an act clearly dangerous to human life that caused the death of an individual”.

The six-year veteran of the department, who is white, was fired on Tuesday for failing to adhere to its policies. In 2013, according to records obtained by the Associated Press, he was suspended for 16 hours and ordered to take an anger management course after a complaint from the Dallas County district attorney’s office that alleged vulgar and aggressive behaviour in the office and in court.

Modern de-escalation techniques emphasise calm communication under pressure. But in 2015 the Balch Springs force was happy to show local media body camera footage of an encounter with an unarmed and uncooperative car theft suspect that it appeared to consider a model of restrained policing. Pointing his gun, an unnamed officer repeatedly yelled and swore at the man, telling him: “Get on the ground, don’t reach in your pocket motherfucker, I will kill you!”

Balch Springs is a nondescript suburb of about 25,000 people 13 miles east of downtown Dallas. The police force does not reflect the ethnic makeup of the community. According to 2015 figures from Reporting Texas, though only about a quarter of the population is white, some 80% of Balch Springs officers are white.

After five officers were killed during a shooting rampage in downtown Dallas last July, said Michael Waters, a Dallas pastor who spoke at Thursday’s vigil, the city tried to give the appearance of a united front between the community and police, overlooking tensions caused by numerous instances of unpunished police brutality.

“While that was the narrative promoted to the nation and the world, those of us in this city know a far different story,” Waters said.

“There are a number of persons who have died tragically within our city over many decades and while Jordan Edwards is the headline, we are not just fighting for the memory of Jordan Edwards and for justice for him, but for many other families who still today have not received the justice they rightfully deserve.”