Racial anger bubbled over again in Ferguson, the troubled Missouri town plagued by violence since August, when two police officers were injured in a shooting at a protest on Thursday morning.
The St Louis suburb has become a microcosm for a debate raging in the US since the police killing of unarmed black teenager Michael Brown last summer: is heavy-handed policing a symptom of deeply ingrained racial disparities across the American criminal justice system?
A week ago, Barack Obama, the US's first black president, spoke eloquently in a stirring speech at the 50th anniversary of the historic civil rights march in Selma, Alabama, saying that it showed how "non-violent change is possible".
Early on Thursday morning, during a protest against racially biased policing in Ferguson, one officer was shot in the face and another was shot in the shoulder. Although both sustained non-life-threatening injuries, the town was again engulfed in fear and mistrust.
A crowd had gathered to protest following the resignation of police chief Thomas Jackson. He stood down after an excoriating department of justice report found a culture of systemic racial bias in Ferguson's police department and a courts system stacked against black people, raising money by targeting the poor and minorities with fines.
The Obama administration has tried to quell tensions, by condemning the shootings while saying that some protesters were right.
"What had been happening in Ferguson was oppressive and objectionable and was worthy of protest," Obama said during an appearance on late-night talk show Jimmy Kimmel Live. "But there was no excuse for criminal acts, and whoever fired those shots shouldn't detract from the issue. They're criminals."
A half-century on from the violence against peaceful black protesters at Selma, the Ferguson report found that little had changed, at least in one town.
From 2012 to 2014, African-Americans were the targets of 90 per cent of the recorded use of force, despite being only two-thirds of the population of the town. In parallels with Selma, only African-Americans were bitten by police dogs. There was "no alternative explanation" except racial bias, said US attorney general Eric Holder.
As racial tensions grow, shots were heard this week, not voices.