Three former Minneapolis police officers were found guilty of depriving George Floyd of his rights by failing to give aid to the handcuffed black man pinned beneath a colleague's knee.
The jury's verdict against Tou Thao, J. Alexander Kueng, and Thomas Lane, came in a case that hinged on when an officer has a duty to intervene in another's misconduct.
It is a rare instance of police officers being held criminally responsible for a colleague's excessive force.
Federal prosecutors argued in the US District Court in St. Paul that the men knew from their training and from "basic human decency" that they had a duty to help Mr Floyd as he begged for his life before falling limp beneath the knee of the defendants' former colleague, Derek Chauvin.
Mr Floyd's killing sparked protests in cities around the world against police brutality and racism.
Chauvin, who is white, was convicted of Mr Floyd's murder at a separate state trial last year and sentenced to more than 22 years in prison.
Former Minneapolis police officers J. Alexander Kueng, Thomas Lane and Tou Thao Credit: AP
Although race was not a part of the state or federal charges, Chauvin's conviction was seen as a landmark rebuke of the disproportionate use of police force against black Americans.
In December, Chauvin pleaded guilty to the federal charge of violating Floyd's rights during the arrest in a Minneapolis intersection on 25 May 2020.
Under Chauvin's plea agreement, federal prosecutors are expected to ask at an as-yet unscheduled hearing for a 25-year sentence to run concurrently with his state prison sentence. His three former colleagues face years in prison on the federal charges, and are also due to stand trial in Minneapolis in June on state charges of aiding and abetting Floyd's murder.
Widely seen mobile phone footage showed Chauvin, 45, grinding his knee on Mr Floyd's neck for more than nine minutes as horrified onlookers yelled at him to get off.
Children put lights in front of a mock headstone bearing the name of George Floyd at a makeshift memorial to people killed by the police in Minneapolis. Source: The New York Times
Thao could be seen steps away from Chauvin, telling onlookers to stay on the pavement and rebuffing their concerns. Kueng and Lane were to Chauvin's right, pinning down Floyd's buttocks and legs.
All three testified in their own defence. Each acknowledged they knew they had a duty of care to people in their custody.
But they and their lawyers told jurors they did not realise at the time that Mr Floyd was in dire need of medical aid or that Chauvin's use of force was excessive and so they could not have been acting with deliberate indifference.
To rebuff this, prosecutors repeatedly played videos showing Mr Floyd's distress was plain to bystanders, including children and an off-duty firefighter, who shouted that Mr Floyd was passing out and begging the police to check his pulse.
The three defendants all described deferring to the authority of Chauvin, the most senior officer at the scene with 19 years at the Minneapolis Police Department. They said they assumed he must know what he was doing.
Kueng, 28, and Lane, 38, who first handcuffed Floyd on suspicion of using a fake $20 note in a nearby store, also noted they were rookies only a few days out of training, which lasted more than a year. Thao, 36, had been on the force for eight years.
