The judge in the George Floyd murder case has refused a request by the defence attorney of Derek Chauvin to sequester the jury following unrest sparked by the police shooting of a Black man in a nearby suburb.
Violent protests erupted in Brooklyn Center, Minneapolis, on Sunday following the death of 20-year-old Daunte Wright who was shot by police during a traffic stop.
Defence Attorney Eric Nelson argued on Monday, the morning after unrest, that jurors could be influenced by the prospect of what might happen as a result of their verdict.
"Ultimately, your honour, the question becomes will the jury be competent to make a decision regardless of the potential outcome of their decision," Mr Nelson said.
Judge Peter Cahill said he would not sequester the jury until next Monday, when closing arguments are expected to begin.
He also denied a defence request to question jurors about what they might have seen in relation to the unrest.
In the wake of the shooting, hundreds of protesters broke into about 20 businesses at a shopping centre, jumped on police cars and hurled rocks and other objects at police.
Officers in riot gear fired gas and flash-bang grenades.
Prosecutor Steve Schleicher argued against sequestering the jury, saying: "I don’t think that would be an effective remedy."
"World events happen," he added. "And we can’t have every single world event that might affect somebody’s attitude or emotional state or anything be the grounds to come back and re-voir dire [ask questions to ensure a freedom of bias] all the jurors."
The judge had previously asked jurors to avoid news during the trial.
The ruling came as the trial entered its third week, with the prosecution close to wrapping up its case and giving way to the start of the defence.
On Monday morning, Dr Jonathan Rich, a cardiology expert from Northwestern Memorial Hospital in Chicago, echoed earlier experts in saying that Floyd died of low oxygen levels from the way he was held down by police.
He rejected defence theories that Floyd died of a drug overdose or a heart condition.
"It was the truly the prone restraint and positional restraints that led to his asphyxiation," Dr Rich said.
He added: "Every indicator is that Mr. Floyd had actually an exceptionally strong heart."
Dr Rich, who said he had reviewed Floyd’s autopsy report, claimed that some narrowing of the arteries is extremely common, and that Floyd had a mildly thickened or mildly enlarged heart but that that would be normal in someone with high blood pressure.
He said Floyd was "restrained in a life-threatening manner", noting among other things that he was facedown on the ground, a knee was on his neck, his hands were cuffed behind his back and being pushed upward, and a knee was on the lower half of his body.
Dr Rich said that as one officer noted on video that Floyd was passing out, police probably still could have saved his life if they had repositioned him so that his lungs could expand again.
Once an officer noted that Floyd’s pulse had stopped, police still had a significant opportunity to save his life by administering CPR, he added.
Former Minneapolis police officer Chauvin, 45, is charged with murder and manslaughter in connection with Mr Floyd's death on May 25 last year.
Prosecutors say Chauvin had his knee on Floyd’s neck as the 46-year-old Black man lay pinned to the pavement for 9.5 minutes.
Video of Floyd, pinned down by Chauvin and two other officers sparked protests around the US and internationally.
The defence team are expected to call their own medical experts to make the case that it was not Chauvin's knee that killed Floyd.
They have not confirmed whether Chauvin will give evidence in the trial.