Criminal charges have been dropped against two policemen filmed knocking a 75-year-old protester to the ground in New York last year, prosecutors say.
A grand jury declined to indict Buffalo officers Robert McCabe and Aaron Torgalski on assault charges.
The officers were seen on video in June shoving activist Martin Gugino, who fell over and started bleeding.
He spent about a month in the hospital with a fractured skull and brain injury.
The incident drew national outrage at the height of protests over the killing of black man George Floyd in police custody in Minneapolis last year.
The episode in Buffalo was filmed outside the town hall of the city, where Mr Torgalski and Mr McCabe were enforcing a curfew that had been imposed because of the protests.
The officers, both members of the Emergency Response Team of Buffalo Police, were suspended without pay after footage of the incident went viral.
Fifty-seven of their colleagues – the entire unit – later resigned from the team in response to the suspensions.
Prosecutors charged the officers with assault in June, accusing them of pushing “a protestor outside of City Hall, causing him to fall and hit his head on the sidewalk”.
Both officers pleaded not guilty and were released without bail.
On Thursday, Erie County District Attorney John Flynn, who brought the charges against the officers, said a grand jury had dismissed the case.
A grand jury is set up by a prosecutor to determine whether there is enough evidence to pursue a prosecution. In legal terms, it determines whether probable cause exists to believe a crime has been committed.
Addressing criticism that the case had been delayed, Mr Flynn said prosecutors made a thorough presentation. But Mr Flynn said he could not reveal why the grand jury – which held proceedings in secret – came to the conclusion it did.
“As with all cases, since that date of arrest, an investigation continued and was pursued,” Mr Flynn said at a news conference. “There was a felony charge and, therefore, it was a matter that was going to go to the grand jury. Let’s be clear here, OK? This really wasn’t a complex case.”
“The video that was taken speaks for itself,” Mr Flynn added.
The Buffalo Police Benevolent Association said it was pleased with the grand jury’s decision.
“As we have stated all along, Officers McCabe and Torgalski were simply following departmental procedures and the directives of their superiors to clear Niagara Square despite working under extremely challenging circumstances,” the union said.
The decision has been criticised by others, including Victoria Ross, the executive director of Western New York Peace Center.
“The problem is state-sponsored violence is excused,” Ms Ross told the New York Times. “If somebody is wearing a uniform, it’s excused. And violence being excused at any level is a problem.”