Los Angeles (AFP) - Three decades ago, a bystander's grainy video of US police officers savagely beating a motorist eventually led to their trial.
Their acquittal a year later for the attack on Rodney King set Los Angeles ablaze, as anger over police violence erupted across the city, with riots that left dozens dead and wrought $1 billion in damage.
Now the United States is once again bracing for fury with the release of footage of five Memphis policemen pummeling 29-year-old Tyre Nichols.
He died of his injuries three days later on January 10.
The five, all of whom are Black, have been fired, and charged with second-degree murder and other felonies.
The relative speed with which authorities moved stands in marked contrast to official reaction in the wake of Rodney King's beating.
But both instances gained notoriety because of the existence of graphic visual proof of police brutality, said Jack Glaser, a specialist in racial bias in policing at the University of California, Berkeley.
"Before Rodney King, there weren't a lot of people with video cameras, and the fact that somebody had a video camera and was able to capture that caused that to gain national attention," he told AFP.
"Now, that's ratcheted up exponentially with everybody constantly carrying (smartphones) in addition to the police wearing body cameras."
The existence of footage -- whether captured by police or by bystanders -- helps to drive efforts to hold police accountable.
"In the absence of that, there tends to be a fair amount of obstruction and a lot of police union activism to protect jobs."
'Very rare'
Patrick Oliver, a former police chief in Cleveland, Ohio, who is now director of the criminal justice program at Cedarville University, agreed that the relative speed with which authorities had acted was because of the existence of such damning proof.
"It's very rare" to move so quickly against officers, he told AFP.
"The Memphis Police Department basically believe that they had sufficient evidence to justify their administrative charges."
The decision to get the video out in the public domain so quickly was a strategic one, intended as a partial balm, he said.
"The video footage is being released after the officers have been terminated and the criminal indictments have been announced.
"People who are justifiably outraged by it will know that the police department took action against all five of these officers, and that the state's attorney has already taken criminal action."
'Above the waterline'
Lora Dene King, who was seven years old when her father was beaten in 1991, said Nichols' death was part of a long line of police brutality that stretched from her dad to the "I can't breathe" chokehold death of Eric Garner in 2014, to the murder in Minneapolis of George Floyd in 2020.
"The whole situation is sickening to me, there is no reason he shouldn't be alive," she said of Nichols.
"It'll just be another hashtag and we'll go on with our lives, and then it'll happen again."
UC Berkeley's Glaser said there was a cultural shift under way that recognized the prevalence of police violence against Black men.
"There's an increasing understanding by police leaders that they can't just throw up the blue wall...and that there is going to be accountability."
But, he said, headline-grabbing incidents like the death of Tyre Nichols were just "those above the waterline" that we become aware of because of the video and because of the level of violence involved.
"This is the thing that indicates how bad the biases are and how out-of-kilter the policing mindset is."
