Hundreds of protesters have been gathering nightly outside the Brooklyn Center police station near Minneapolis since former officer Kim Potter, who is white, shot a 20-year-old Black motorist during a traffic stop on Sunday.
Demonstrators have thrown fireworks, attempted to tear down a security fence, and lobbed water bottles at officers.
Long lines of riot police have driven away protesters with tear gas, rubber bullets, flash grenades. The officers' tactics have angered civic representatives.
It's one of many recent videos revealing incidents of police violence and shootings.
Chicago police shoot 13-year-old
A separate video of Chicago police fatally shooting a 13-year-old has also provoked grief and outrage.
The video from Chicago shows Officer Eric Stillman shooting 13-year-old Adam Toledo as he turns toward Stillman and raises his hands. Police said he had a handgun.
The video will be key evidence for prosecutors who face a dilemma over the strong emotions surrounding the case and legal precedent that makes it difficult to bring charges against law enforcement in Chicago.
Around a thousand people gathered on Friday evening in a park on Chicago's northwest side, some holding signs that read, "stop killing kids."
A brass band played music as the crowd chanted, "no justice, no peace".