Warning: There are distressing images of police violence towards Tyre Nichols in this report by Robert Moore
After the George Floyd murder nearly three years ago, we dared to hope that policing in America would change forever.
We imagined that such a brazen, lethal assault would never happen again. We believed the police chiefs who promised rogue officers would be identified and would lose their badge and their gun.
But here we are. This weekend, another American city is baffled and shocked at appalling police conduct caught on camera.
This time it was not passers-by who filmed the scene but the officers themselves, on their own body cameras.
What started as a traffic stop in this impoverished corner of east Memphis became an assault of unfathomable brutality.
At one point, 29-year-old Tyre Nichols flees for his life before officers catch up with him again. The next three minutes are hard to watch - he is pepper sprayed and is calling in desperation for his mother. He is just metres from her house.
The video from the officers' body-cams and from a street security camera then capture Mr Nichols being savagely kicked, and receiving a beating that leaves the 29-year-old severely injured.
Almost as shocking as the violence is the cavalier attitude of the officers who stand around providing no immediate assistance.
'Blood is in the police department's hands'
Finally, Mr Nichols is propped up against a car. He is eventually taken to hospital but dies three days later.
Hours after the video was released last night, we watched as protesters took to the streets of Memphis - blocking a bridge that connects Tennessee and Arkansas.
The demands were echoes of what we heard in Minneapolis after the George Floyd murder and in a dozen other US cities - that black lives matter, that justice must be done, that policing must change.
America is on edge once more. The national reckoning over the value of black lives - and the anguished debate over police brutality - has been reignited.
There is fury among protesters right across the US
Five Memphis police officers - themselves all black - now face murder, assault and kidnapping charges.
The hour-long video will be the devastating evidence presented by prosecutors at the trial.
The court case will be a verdict not just on the officers' conduct that night.
It will also be another excruciating judgement on the culture of policing in America.
Want a quick and expert briefing on the biggest news stories? Listen to our latest podcasts to find out What You Need To Know