Former Minneapolis police officer Derek Chauvin was on Tuesday convicted of murder and manslaughter in the death of George Floyd, a black man who died after Chauvin, who is white, knelt on his neck for more than nine minutes.
The videotaped killing sparked global protests and brought centuries of racial injustice in the US into the spotlight.
A racially diverse jury of seven women and five men in the Midwestern city of Minneapolis deliberated for only about 10 hours after a three-week trial to find Chauvin guilty in unanimous decisions on all three charges he faced.
Chauvin, 45, could spend up to 40 years behind bars for the May 25, 2020, killing when he is sentenced in about eight weeks, but will likely receive a shorter sentence as per legal guidelines.
He was remanded into custody and led out of the courtroom in handcuffs.
Chauvin was convicted of second-degree unintentional murder, third-degree murder and second-degree manslaughter.
Floyd died as Chauvin knelt on his neck during an arrest over an allegedly counterfeit $20 bill.
Hundreds of people cheered outside the Hennepin County Court as the verdicts were announced, while National Guard members surrounded the building and helicopters buzzed overhead.
In the hours after the verdict was announced, thousands of people gathered at the site of Floyd’s killing, which has been transformed into George Floyd Square.
Families with young children mingled and laughed as a man played the sousaphone.
Nia Stork, 18, came with her friends to bear witness to the moment.
“It means a lot,” she said. “This is just the beginning and it’s a beautiful start to finally have justice."
In a call to Floyd's family members, US President Joe Biden said he was relieved by the verdict.
"Nothing is going to make it better but at least, God, now there's some justice," Mr Biden said.
He promised to pass legislation for police reform in the US and to deal with "systemic racism".
Family lawyer Ben Crump posted a recording of Mr Biden's call online.
Minnesota State Attorney Keith Ellison said true justice had not been served.
"I would not call today's verdict justice," Mr Ellison said. "Justice implies true restoration, but it is accountability that is the first step towards justice."
Former president Barack Obama issued a statement saying: "Today, a jury did the right thing."
The mood downtown was mostly relieved and jubilant, with hundreds of people preparing to march through Minneapolis in celebration of the verdict.
The sound of car horns could be heard for hours after the verdict as traffic ground to a halt and people celebrated by waving Black Lives Matter flags out side their car windows.
They chanted: "Say his name, say his name: George Floyd."
Donald Nelson, 52, said Minneapolis would be spared new unrest.
"They saved the city and the country with this guilty verdict," Mr Nelson told The National.
Jamar Nelson, 42, said he felt "so validated. It’s a shot across the bow to police".
“We’re going to party like it’s 1999 tonight and tomorrow we’re going to start the healing process.”
Brandyn Tulloch, one of the main organisers of the recent demonstrations, said he was shocked by the verdict. "This was the last thing I was expecting, this was the last thing I was preparing for today," he told The National.
"It's a lot of emotions, but it shouldn't have to feel like this. It took almost a year for them to [call] a murder that we all saw was murder."
Mr Tulloch believed the city was doubting the outcome as well. "The way they fortified downtown, the way they brought in the National Guard, the way they brought in other agencies, they were preparing for the worst."
Minneapolis had been bracing for demonstrations for days, with fencing, concrete barriers, heightened security and boarded-up windows throughout the city's downtown area.
About 3,000 service members of the Minnesota National Guard are stationed in the city.
Other US cities – including Chicago, Philadelphia, and Washington DC – had also been preparing for unrest after the jury’s verdict.
Activists have held gatherings and protests in Minneapolis for about a year, and a recent police shooting that resulted in the death of Daunte Wright, another black man, in the nearby suburb of Brooklyn Centre, also reignited demonstrations.
Chauvin's trial was widely followed and covered by US and global media, with every step of the proceedings streamed live in a first for the state of Minnesota.
Hennepin County District Judge Peter Cahill said cameras were needed for coronavirus mitigation during the trial.
Photos and video of Floyd’s killing fuelled nationwide protests in the summer and spring of 2020, under the Black Lives Matter movement that some observers said grew to become the largest in US history.
Video was a key part of the court proceedings and was examined extensively by people called to the stand, including experts, former and current members of the Minneapolis police department and others.
The prosecution stressed how Chauvin breached police policy, did not give Floyd medical attention and kept his knee on his neck even after he died.
The defence looked at other factors into how Floyd may have died, such as drug use, health conditions or external causes.
Each count against Chauvin carries a different maximum sentence: 40 years for second-degree unintentional murder; 25 years for third-degree murder; and 10 years for second-degree manslaughter.
On Tuesday evening, Mr Biden and Vice President Kamala Harris spoke about the verdict.
"It was a murder in full light of day," Mr Biden said. "And [it] ripped the blinders off for the whole world to see the systemic racism."
"There can never be any safe harbour for hate in America."
"Today we feel a sigh of relief," Ms Harris said.
However, she added, "a measure of justice is not the same as equal justice. This verdict brings us a step closer. We still have work to do. We still have to reform the system."
"We have to listen: 'I can't breathe. I can't breathe.' Those were George Floyd's last words. We can't let those words die with him," Mr Biden said. "This can be a moment of significant change."