Prosecutors charged three more police officers Wednesday in the death of George Floyd and filed a new, tougher charge against the officer at the center of the case.
The move delivered a victory to protesters who have filled the streets from coast to coast to fight police brutality and racial injustice.
The most serious charge was filed against Derek Chauvin, who was caught on video pressing his knee to Floyd's neck and now must defend himself against an accusation of second-degree murder.
The three other officers at the scene were charged for the first time with aiding and abetting second-degree murder and second-degree manslaughter.
All four were fired last week. If convicted, they could be sentenced to up to four decades in prison.
Chauvin was initially charged with third-degree murder and second-degree manslaughter. Those charges still stand.
The new second-degree murder charge alleges that Chauvin caused Floyd's death without intent while committing another felony, namely third-degree assault.
It carries a maximum penalty of 40 years in prison, compared with a maximum of 25 years for third-degree murder.
The other officers — Thomas Lane, J. Kueng and Tou Thao — face the same maximum penalties for aiding and abetting. All three men were in custody by Wednesday evening. Chauvin was arrested last week and is still being held.
The multiple charges against each officer would offer a jury more options to find them guilty.
The charges were sought by Minnesota Attorney General Keith Ellison, who called the protests unleashed by the death "dramatic and necessary" and said Floyd "should be here and he is not."
"His life had value, and we will seek justice," said Ellison, who cautioned that winning convictions would be hard and said that public pressure had no bearing on his decisions.
Hundreds of protesters were in New York City's Washington Square Park when the charges were announced.
Ben Crump, an attorney for Floyd's family, called it "a bittersweet moment" and "a significant step forward on the road to justice." Crump said Elison had told the family he would continue his investigation into Floyd's death and upgrade the charge to first-degree murder if warranted.
The move by prosecutors punctuated an unprecedented week in modern American history, in which largely peaceful protests took place in communities of all sizes but were rocked by bouts of violence, including deadly attacks on officers, rampant thefts and arson in some places.
Nationwide, more than 9,000 have been arrested in connection with unrest. At least 12 deaths have been reported, though the circumstances in many cases are still being sorted out.
Minnesota has opened a civil rights investigation into whether the Minneapolis Police Department has a pattern of discrimination against minorities.
President Donald Trump has pushed the nation's governors to take a hard line against the violence. He again tweeted Wednesday: "LAW & ORDER!"
Within hours, thousands of peaceful protesters were in the streets again in the nation's capital, singing "Amazing Grace" as they knelt under the watch of law enforcement officers in riot gear. "We are not going anywhere!" they chanted.
The protests have also taken root overseas.
In Greece, police fired tear gas after young people attacked them Wednesday outside the U.S. Embassy in Athens. Some 4,000 protesters had been peaceful until near the end of the demonstration, when some threw gasoline bombs and stones at police. No injuries or arrests were reported. Other protests were held Wednesday in London, Helsinki, Rotterdam and Bogota, among other cities.
—AMY FORLITI, STEVE KARNOWSKI and TIM SULLIVAN