George Floyd begged for help with his "very last breath" but received no compassion from Derek Chauvin, the prosecution said in closing arguments at the murder trial of the former police officer.
"George Floyd begged until he could speak no more," prosecutor Steve Schleicher told the jury in a Minneapolis courtroom.
"All that was required was a little compassion and none was shown on that day."
"It may be hard for any of you to imagine a police officer doing something like this", he told the jury, as he asked the panel to lay aside "the way we think of police officers".
Mr Chauvin, 45, is charged with second-degree murder and manslaughter and third-degree murder.
Prosecutors say they have met the burden of proof for all three charges, telling jurors: "He [Mr Chauvin] did this on purpose".
The case of Mr Chauvin, a white ex-officer filmed kneeling on Mr Floyd for more than nine minutes, laid bare racial wounds in the United States and has come to be seen as a pivotal test of police accountability.
But Mr Schleicher told jurors to ignore the national debate raging outside the courtroom.
"To be very clear, this case is called the state of Minnesota versus Derek Chauvin, this is not called the state versus the police," he said.
"Policing is a noble profession," he said, adding "there's nothing worse for good police than bad police", who do not follow the rules, procedure or training.
Mr Chauvin, a 19-year veteran of the Minneapolis Police Department, faces a maximum of 40 years in prison if convicted of the most serious charge - second-degree murder.
Footage of Mr Chauvin pressing the handcuffed black man face down as he called "I can't breathe", sparked protests against racial injustice and police brutality around the world.
The harrowing video was shown repeatedly to the jury during Mr Chauvin's three-week trial.
Eric Nelson, Mr Chauvin's attorney, said at the opening of the trial that there was "no political or social cause" in the courtroom, but it has coincided with rising tensions from two other high-profile police killings.
Daunte Wright, a 20-year-old black man, was shot dead in a Minneapolis suburb on April 11 by a white policewoman who apparently mistook her gun for her Taser, and a 13-year-old boy was killed by police in Chicago.
Mr Wright's killing triggered several nights of protests in Minneapolis, and ahead of a verdict in Mr Chauvin's case National Guard troops have been deployed in the Minnesota city where shop windows have been boarded up as a precaution.
With tensions high as a possible verdict nears, two guard members were slightly injured after at least one person opened fire from a car on a team of troops and police early on Sunday in Minneapolis, authorities said.
"The outcome that we pray for in Derek Chauvin is for him to be held criminally liable for killing George Floyd," said Ben Crump, an attorney for the Floyd and Wright families.
"Killing unarmed Black people is unacceptable," Mr Crump told ABC News on Sunday. "We have to send that message to the police.
"Hold police officers accountable."
Among the 38 witnesses who testified for the prosecution were some of the bystanders who watched Mr Floyd's May 25, 2020 arrest for allegedly using a counterfeit $20 bill to buy a pack of cigarettes.
Darnella Frazier, the teenager who took the video that went viral, said Mr Floyd was "scared" and "begging for his life."
"It wasn't right. He was suffering," Ms Frazier said.
Genevieve Hansen, 27, an off-duty firefighter, said Mr Chauvin and other officers rebuffed her offers to provide medical attention to Floyd.
Donald Williams, 33, said he called 911 to report a "murder" after Mr Floyd was taken away in an ambulance.
Mr Chauvin attended every day of the trial, dressed in a suit and taking notes on a yellow legal pad.
He spoke only once - and that was out of the presence of the jury - when he invoked his Fifth Amendment right not to testify in his own defence.
David Schultz, a law professor at the University of Minnesota and Hamline University, said he was not surprised by Mr Chauvin's decision.
"The chances of him helping himself probably weren't going to be too good," Mr Schultz said.
"I could imagine a scenario where the prosecution would play that nine minute and 29 second tape and ask Derek Chauvin what he was thinking when George Floyd said he can't breathe."
Much of the evidence phase of the trial involved testimony from medical experts about Mr Floyd's cause of death and whether Mr Chauvin had engaged in reasonable or excessive use of force.
A retired forensic pathologist put on the stand by the defence said Mr Floyd died of cardiac arrest brought on by heart disease and the illegal drugs fentanyl and methamphetamine.
Medical experts called by the prosecution said Mr Floyd died from hypoxia, or a lack of oxygen, from Mr Chauvin's knee on his neck and that drugs were not a factor.
The defence also called a retired police officer who said Mr Chauvin's use of force against Mr Floyd was "justified."
Police officers testifying for the prosecution - including the city police chief - said it was excessive and unnecessary.
Mr Schultz, the law professor, said the state had presented a strong case.
"They had to overcome the barrier of being able to prosecute police officers," he said. "Police officers have strong legal authority to use force."
A conviction on any of the charges - second-degree murder, third-degree murder or manslaughter - will require the jury to return a unanimous verdict.
Mr Shultz said the defence, which called only seven witnesses, "may be hoping to persuade just one juror to get a hung jury."
The racially diverse jury is made up of three white women, three black men, three white men, two mixed race women and one black woman.
They will be sequestered for deliberations after closing arguments.
Three other former police officers - Tou Thao, Thomas Lane, and J. Alexander Kueng - also face charges in connection with Mr Floyd's death.
They are to be tried separately later in the year.