A former police officer who pressed his knee into George Floyd’s neck until well past Floyd’s final breath was found guilty of murder on Tuesday in a case that shook the nation’s conscience and drew millions into the streets for the largest racial justice protests in generations.

The verdict, which could send the former officer, Derek Chauvin, to prison for decades, was a rare rebuke of police violence, following case after case of officers going without charges or convictions after killing Black men, women and children.

At the centre of it all was an excruciating video, taken by a teenage girl, that showed Chauvin, who is white, kneeling on the neck of Floyd, who was Black, for nine minutes and 29 seconds as Floyd pleaded for his life and bystanders tried to intervene. Floyd repeated “I can’t breathe” more than 20 times during the encounter.

The video, played on a horrifying loop for the past year, triggered more than calls for changes in policing. It stirred Americans of all races, in small towns and large cities, to gather for mass protests, chanting “Black lives matter” and challenging the country to finally have a true reckoning over race.

Their demands reverberated within the walls of institutions that had long resisted change, from corporate America to Congress.

This week, over the course of two days, a racially diverse jury of seven women and five men deliberated for about 10 hours before pronouncing Chauvin guilty on all three charges: second-degree murder, third-degree murder and second-degree manslaughter.

President Biden praised the verdict in a nationwide address at the White House but called it a “too rare” step to deliver “basic accountability” for Black Americans.

“It was a murder in full light of day, and it ripped the blinders off for the whole world to see,” Biden said. “For so many, it feels like it took all of that for the judicial system to deliver just basic accountability.”

Hours before the jury came back with a decision, Biden had taken the unusual step of weighing in, telling reporters that he was “praying” for the “right verdict”.

“This can be a giant step forward in the march toward justice in America,” he said.

After the verdict, Philonise Floyd, one of Floyd’s younger brothers, spoke at the Hilton hotel in downtown Minneapolis. “We are able to breathe again,” he said, holding back tears.

He drew a line from his brother back to Emmett Till, a Black child who was lynched in Mississippi in 1955.

“We ought to always understand that we have to march,” he said. “We will have to do this for life. We have to protest because it seems like this is a never-ending cycle.”

People gathered at the intersection where Floyd was killed, now known as George Floyd Square, and the word “Guilty” rippled throughout the crowd after the verdict was announced, prompting cheers and sobs. The crowd began to chant, “Black lives matter.”

Chauvin, who had been free on bail during the trial, was ordered into custody by the judge, Peter A. Cahill, and was taken out of the courtroom in handcuffs.

The verdict was hailed across the country by civil rights leaders and honking motorists. It gave a tense nation a moment to exhale, even as recent police killings in a Minneapolis suburb, Chicago and, on Tuesday afternoon, Columbus, Ohio, sent Americans back into the streets, holding signs that asked, “How many more?”.

The case was handled by the office of attorney-general Keith Ellison, the first Black man to hold statewide office in Minnesota.

Prosecutors mounted perhaps the most ambitious and extensive case in any trial of an officer for an on-duty killing.

With a rotating cast of prominent lawyers, some of whom volunteered their services, the state presented 11 days of testimony from onlookers, paramedics, fellow police officers and a phalanx of medical experts armed with formulas, charts and timelines.

Among the state’s star witnesses was the chief of the Minneapolis police, Medaria Arradondo, who said Chauvin had “absolutely” violated training, ethics and several department policies when he kept Floyd pinned facedown on the street long after he stopped breathing. It is exceedingly rare for a chief to testify against an officer from his own department.

The presumptive sentence for the most serious charge, second-degree murder, is 12.5 years, according to Minnesota’s sentencing guidelines. But the prosecution has asked for a lengthier sentence, arguing that there were children present at the scene, that Chauvin treated Floyd with “particular cruelty” and that he “abused his position of authority”.

George Floyd, 46, was a grandfather, a rapper known as Big Floyd and a security guard who had lost his job during the coronavirus pandemic. On the day he died — May 25, 2020 — the Minneapolis police responded to a call saying that he had used a counterfeit $20 bill to buy cigarettes at a corner store, Cup Foods.

Floyd initially cooperated with officers but he balked at getting into the back of a squad car, saying he was claustrophobic.

A struggle ensued that resulted in three officers holding him prone on the street and one standing guard.

Chauvin was a field training officer and the senior officer at the scene, with 19 years on the force.

As he knelt on Floyd, sometimes with both knees, he dismissed concerns or suggestions raised by the other officers that Floyd was passing out, had no detectable pulse and should be moved onto his side, a less dangerous position.

When Floyd said, “You’re going to kill me, man,” Chauvin replied: “Then stop talking, stop yelling. It takes a heck of a lot of oxygen to talk.”

Chauvin continued to kneel on him for about three minutes after Floyd drew his final breath, according to expert testimony.

The four officers involved were fired the next day. The other three — Thomas Lane, J. Alexander Kueng and Tou Thao — have been charged with aiding and abetting murder and are expected to be tried in August.

Prosecutors began their case against Chauvin with a series of eyewitnesses to Floyd’s death, who offered emotional testimony about the trauma and guilt they were left with.

While Chauvin’s lawyer, Eric J. Nelson, attempted to paint those bystanders — who had been out to buy a cellphone cord or a drink, or just to take a walk — as a dangerous and unruly mob, each offered an account of the desperation and helplessness he or she felt watching Floyd become unconscious beneath the officer’s knee.

“They saw that a human being they did not know was suffering,” Jerry W. Blackwell, one of the prosecutors, said in his closing argument, calling them a “bouquet of humanity”.

He added, “And they wanted to try to intervene to stop the suffering.”

New York Times News Service