Five police officers have been charged with federal civil rights violations for their role in beating a 29-year-old black man at a traffic stop in Memphis.
The officers were already facing state charges for the 7 January beating of Tyre Nichols, who died three days later in hospital.
Video footage showed the officers kicking and punching Mr Nichols after he was pulled over.
The pictures sparked protests against police brutality in the US.
They all pleaded not guilty to state charges in February, including second-degree murder and aggravated assault and kidnapping.
The officers – Tadarrius Bean, Demetrius Haley, Desmond Mills Jr, Emmitt Martin III and Justin Smith – now face new civil rights, conspiracy and obstruction offences.
Federal charges are ones that violate federal laws enacted by Congress. They are brought by the Department of Justice and usually carry stiff sentences.
The new indictment alleges the defendants did not tell dispatchers, their supervisor or emergency medical crews that they knew Mr Nichols had been repeatedly hit.
It also says the officers limited use of their body cameras at the scene to control the amount of evidence captured. Haley and Smith activated their body cameras only after the assault.
“We all heard Mr Nichols cry out for his mother and say, ‘I’m just trying to go home,'” Attorney General Merrick Garland said in a video statement after the indictment. “The Justice Department will continue to hold accountable officers who betray their oath.”
In May, an autopsy report found Mr Nichols died of blunt force injuries, suffering brain injuries and wounds to his head and elsewhere on his body.
The Memphis Police Department fired the officers after the attack. The department is facing a lawsuit from the Nichols family, which alleges the city’s negligent hiring practices and poor training led to their son’s death.
The five defendants could face up to life in prison for the two counts of deprivation of rights under colour of law alone. And if convicted on murder charges from the state, they face up to 60 years in prison.