The three Minneapolis police officers who took part in the arrest of George Floyd as a fourth planted a knee on his neck have been charged with aiding and abetting murder.
State prosecutors have also upgraded the charge brought last week against the fourth officer, Derek Chauvin, from third-degree murder to second-degree murder. Mr Chauvin was arrested last week, and arrest warrants for the other three officers have been issued.
“I strongly believe these developments are in the interest of justice for Mr Floyd, his family, community and our state,” Keith Ellison, Minnesota attorney-general, said at a press conference on Wednesday. The investigation is ongoing, he added.
Benjamin Crump, attorney for the victim’s family, thanked Mr Ellison on Twitter for the action.
“This is a significant step forward on the road to justice,” he said. “That is a source of peace for George’s family in this painful time.”
Mr Crump said the attorney-general told the family that he would continue to investigate and upgrade the charges again to first-degree murder if the evidence called for it.
“These officers knew they could act with impunity, given the Minneapolis police department’s widespread and prolonged pattern and practice of violating people’s constitutional rights. Therefore we also demand permanent, transparent police accountability at all levels and at all times.”
Mr Ellison cautioned on Wednesday that it has proven difficult in the past for prosecutors to secure convictions for police officers at trial.
“Every single link in the prosecutorial chain must be strong,” he said. “It needs to be strong because trying this case will not be an easy thing. Winning a conviction will be hard. I say this not because we doubt our resources or our ability . . . but history does show there are clear challenges here.”
Earlier on Wednesday Floyd’s family had called for the other officers to be arrested.
Amy Klobuchar, the Democratic US senator from Minnesota and former presidential candidate, said of the new charges: “This is another important step for justice.”
The move comes three days after Tim Walz, Minnesota’s Democratic governor, appointed Mr Ellison as lead prosecutor in the case, taking over from Mike Freeman, Hennepin County attorney.
Floyd’s death last week touched off protests against police violence across the US, accompanied in some cases by arson and looting that prompted some governors to activate National Guard units. Police in some cities have responded violently to the protests, firing tear gas and rubber bullets.
Nightly curfews have been imposed on several big cities to quell unrest. A fresh round of demonstrations was already under way again on Wednesday, including protests in Washington, Los Angeles and New York.