The jury in the trial of Derek Chauvin, the ex-Minneapolis policeman accused of killing George Floyd last year, has retired to consider its verdict.
The prosecution told jurors that Mr Chauvin had murdered Mr Floyd, but the defence said their client had correctly followed police training.
The court is being protected by barbed wire, high barriers and armed soldiers from the National Guard.
Cities across the country are bracing for protests regardless of the verdict.
On Monday, the prosecution and defence made their closing statements in a trial that lasted three weeks. The prosecution then had another opportunity to rebut defence arguments before the jury was sent to deliberate.
How did the defence sum up?
Mr Chauvin's lawyer Eric Nelson argued that his client did what any "reasonable police officer" would have done after finding himself in a "dynamic" and "fluid" situation involving a large man scuffling with three officers.
He said Mr Chauvin's body camera and badge were knocked off his chest owing to "the intensity of the struggle".
Mr Nelson also argued that Mr Floyd's drug use was "significant" because the body reacts to opioid use, specifically in the case of someone who had been diagnosed with hypertension and high blood pressure.
The lawyer also argued that his client was unlikely to have intentionally violated use-of-force rules as he would have been aware that the whole interaction was being recorded. "Officers know that they are being videotaped," added Mr Nelson.
How did the prosecution sum up?
Prosecutor Steve Schleicher urged jurors to "use your common sense. Believe your eyes. What you saw, you saw," referring to the video showing Mr Chauvin kneeling on Mr Floyd for more than nine minutes last 25 May.
"This wasn't policing; this was murder," he added.
Prosecutor Jerry Blackwell had the final word on Monday. He said the matter was "so simple that a child can understand it".
"In fact, a child did understand it, when the nine-year-old girl said, 'Get off of him,'" Mr Blackwell said, referring to a young onlooker who objected. "That's how simple it was. 'Get off of him.' Common sense."
What happens now?
The jury will be sequestered to consider testimony from 45 witnesses, including doctors, use-of-force experts, police officers, bystanders and people who were close to Mr Floyd.
The defendant is charged with second-degree unintentional murder, third-degree murder and manslaughter. Mr Chauvin faces up to 40 years in prison if convicted of the most serious charge - second-degree murder.
A conviction on any of the counts against him will require the jury to return a unanimous verdict. A single juror holding out would result in a mistrial, but the state could then try Mr Chauvin again.
Of the 12 jurors, six are white, four are black and two are multiracial. Seven are women and five are men.
How is the US preparing for the verdict?
The footage of Mr Chauvin, who is white, restraining Mr Floyd, a black man, on the floor as he shouted "I can't breathe" spurred months of global protests in 2020.
On Monday the governor of Minnesota, Tim Walz, requested security assistance from the states of Ohio and Nebraska ahead of the verdict.
The Democrat was heavily criticised after more than 1,000 buildings and businesses were damaged in rioting last year.
In the early hours of Sunday, two National Guard members who were providing neighbourhood security in Minneapolis escaped with minor injuries when they were shot at in a drive-by shooting.
What will happen when there is a verdict?
By Tara McKelvey, BBC News, Minneapolis
The streets around the court were quiet on Monday morning, but local residents are waiting to see what will happen once the verdict is reached.
One activist tells me they are planning to hit the streets, regardless of what kind of verdict is rendered.
If the jurors decide that Derek Chauvin is not guilty on all counts, or guilty only of manslaughter - a lesser charge - the activists will march.
But even if he is found guilty on all counts, the activists will still march - "a celebratory protest", as one of them put it.
In that case, the campaigners will take to the streets to show their satisfaction with the verdict, and to demand justice for the others who have died while in police custody.
What else happened in court?
After the jury was sent out on Monday, Mr Nelson argued remarks made by Democratic representative Maxine Waters over the weekend urging protesters to "get more confrontational" may have influenced the jury.
If there is no guilty verdict in Mr Chauvin's trial, the California congresswoman said in Minneapolis, "then we know that we got to not only stay in the street, but we have got to fight for justice".
In response, Judge Peter Cahill said: "I give you that congresswoman Waters may have given you something on appeal that may result in this trial being overturned."
The judge said the failure of elected officials to stop talking about the case in a manner disrespectful to the rule of law was "abhorrent".
However, he said Ms Waters' "opinion really doesn't matter a whole lot", and he dismissed Mr Nelson's motion for a mistrial.