The white Minneapolis police officer who knelt on George Floyd’s neck was arrested and charged with murder Friday, and authorities imposed an overnight curfew to try to stem three nights of often-violent protests that left dozens of stores burned and looted.

Derek Chauvin, 44, was charged with third-degree murder and second-degree manslaughter in the case. He was also accused of ignoring another officer at the scene who expressed concerns about the black man as he lay handcuffed on the ground, pleading that he could not breathe. Floyd had been arrested on suspicion of using a counterfeit bill at a small grocery store.

An attorney for Floyd’s family welcomed the arrest, but said he expected a more serious murder charge and wants all four officers involved to be arrested.

Hennepin County Attorney Mike Freeman said more charges were possible. He said the investigation into the other three officers continues, but authorities “felt it appropriate to focus on the most dangerous perpetrator.”

Meanwhile, Minneapolis Mayor Jacob Frey declared a curfew from 8 p.m. to 6 a.m. on Friday and Saturday. The order said no one can be out in public except emergency responders and people seeking medical care, fleeing danger or those who are homeless.

“I know that whatever hope you feel today is tempered with skepticism and a righteous outrage,” Frey said in a statement. “Today’s decision from the County Attorney is an essential first step on a longer road toward justice and healing our city.”

According to the criminal complaint, Chauvin allegedly disregarded the concerns of another officer, who wanted to roll Floyd onto his side as he was being held down.

The papers also said that an autopsy revealed nothing to support strangulation as the cause of death. The exam concluded that the combined effects of being restrained, potential intoxicants in Floyd’s system and his underlying health issues, including heart disease, likely contributed to his death. Floyd’s family was seeking an independent autopsy.

Police were trying to put Floyd in a squad car when he stiffened up and fell to the ground, saying he was claustrophobic, the complaint said. Chauvin and officer Tou Thoa arrived to help and tried several times to get the struggling Floyd into the car, it said.

At one point, Chauvin pulled Floyd out of the car’s passenger side, and Floyd, who was handcuffed, went to the ground face down. Officer J.K. Kueng held Floyd’s back, and officer Thomas Lane held his legs, while Chauvin put his knee on Floyd’s head and neck area, the complaint said.

When Lane asked if Floyd should be rolled onto his side Chauvin said, “No, staying put is where we got him.” Lane said he was “worried about excited delirium or whatever,” and Chauvin replied, “That’s why we have him on his stomach,” according to the complaint.

After Floyd apparently stopped breathing, Lane again said he wanted to roll Chauvin onto his side. Kueng checked for a pulse and said he could not find one, the complaint said.

In all, Chauvin had his knee on Floyd’s neck for 8 minutes, 46 seconds, including nearly three minutes after Floyd stopped moving and talking, according to the complaint.

Chauvin’s attorney had no comment when reached by The Associated Press.

Freeman, whose home has been picketed by protesters, highlighted the “extraordinary speed” in charging the case just four days after Floyd’s death, but also defended himself against questions about why it did not happen sooner. He said his office needed time to put together evidence, including what he called the “horrible” video recorded by a bystander.

All four officers at the scene of Floyd’s arrest on Monday were fired the next day. After the charges were announced, protesters outside government offices chanted, “All four got to go.”

It was not immediately clear whether Chauvin’s arrest would quiet the unrest, which escalated again Thursday night as demonstrators burned a Minneapolis police station soon after officers abandoned it.

Protests also spread across the U.S., fueled by outrage over Floyd’s death, and years of violence against African Americans at the hands of police. Demonstrators clashed with officers in New York and blocked traffic in Columbus, Ohio, and Denver.

News of the arrest came moments after Minnesota Gov. Tim Walz acknowledged the “abject failure” of the response to the protests and called for swift justice for the officers. Walz said the state had taken over the response to the violence.

“Minneapolis and St. Paul are on fire. The fire is still smoldering in our streets. The ashes are symbolic of decades and generations of pain, of anguish unheard,” Walz said. “Now generations of pain is manifesting itself in front of the world — and the world is watching.”

President Donald Trump threatened action, tweeting “when the looting starts, the shooting starts,” which prompted a warning from Twitter for “glorifying violence.” Trump later said he was referring to shooting that had happened during the protests.

The governor faced tough questions after National Guard leader Maj. Gen. Jon Jensen blamed a lack of clarity about the Guard’s mission for a slow response. Walz said the state was in a supporting role and that it was up to city leaders to run the situation. Walz said it became apparent as the 3rd Precinct was lost that the state had to step in. Requests from Minneapolis and nearby St. Paul for resources “never came,” he said.

“You will not see that tonight, there will be no lack of leadership,” Walz said.

On Friday morning, nearly every building in a shopping district a couple blocks from the abandoned police station had been vandalized, burned or looted. National Guard members carrying assault rifles were lined up at some intersections, keeping people away from the police station. Dozens of volunteers swept up broken glass in the street.

Dean Hanson, 64, lives in a subsidized housing unit nearby, which is home to many older residents. He said his building lost electricity overnight, and residents were terrified as they watched mobs of people loot and burn their way through the neighborhood.

“I can’t believe this is happening here,” he said. “It was pure hell.”

Dozens of fires were also set in St. Paul, where nearly 200 businesses were damaged or looted.

A visibly tired and frustrated Frey, the Minneapolis mayor, took responsibility for evacuating the police precinct, saying it had become too dangerous for officers.

Attorney Benjamin Crump, who is representing Floyd’s family, asked to take custody of Floyd’s body to have an independent autopsy performed. Crump said that talk of a heart condition or asthma was irrelevant because Floyd was walking and breathing before his contact with police.

The doctor who will do the autopsy is Michael Baden, former chief medical examiner of New York City, who was hired to do an autopsy for Eric Garner, a black man who died in 2014 in New York after he was placed in a chokehold by police and pleaded for his life, saying he could not breathe.

State and federal authorities are also investigating Floyd’s death.

The owner of a popular Latin nightclub said Floyd and Chauvin both worked as security guards at the club as recently as the end of last year, but it’s not clear whether they worked together. Chauvin worked at the El Nuevo Rodeo club as an off-duty security guard for nearly two decades, but Floyd had only worked there more recently for about a dozen events featuring African American music, Maya Santamaria told The Associated Press.

Santamaria said if Chauvin had recognized Floyd, “he might have given him a little more mercy.”

Santamaria, who recently sold the venue, said Chauvin got along well with the regular Latino customers but did not like to work the African American nights. When he did, and there was a fight, he would spray people with mace and call for police backup and half-dozen squad cars would soon show up, something she felt was “overkill.”