Democratic presidential candidate Joe Biden has urged charges against police who shot two black Americans, Jacob Blake and Breonna Taylor.
Speaking in Delaware, Mr Biden did not specify what counts should be brought in the cases, which have fuelled racial justice protests nationwide.
The Democrat spoke after notching up a record fundraising haul in August.
He has a lead over President Donald Trump, a Republican, in opinion polls ahead of November's election.
During a news conference in his hometown of Wilmington on Wednesday, Mr Biden was asked whether he agreed with his running mate, Kamala Harris, that the officers in the Blake and Taylor cases should be charged.
"I think we should let the judicial system work its way," he said. "I do think at a minimum, they need to be charged, the officers."
Mr Blake, 29, was shot seven times in the back and paralysed during an arrest in Kenosha, Wisconsin, on 23 August.
No action has so far been taken against the officer involved, pending investigations by the Wisconsin and US departments of justice.
Ms Taylor, 26, was fatally shot in her home during a drug raid in Louisville, Kentucky, on 13 March.
One of the officers is losing his job; two others have been placed on administrative leave as the investigation into their actions proceeds.
Mr Biden also mentioned the gunman, identified in US media as a far-left activist, who fatally shot a Trump supporter on the streets of Portland, Oregon, last weekend.
The Democratic nominee stopped short of calling for charges in that case, but said: "They should be investigated and it should follow through on what needs to be done.
"Let the judicial system work. Let's make sure justice is done."
Mr Biden had been delivering remarks about how to open schools safely in light of the coronavirus pandemic.
His comments came a day before he travels to Kenosha, where he says he wants to help "heal" the city after it was rocked by days of violent protests.
Mr Biden said he had received "overwhelming requests" to visit this latest flashpoint in America's racial reckoning over law enforcement shootings.
The Democrat will meet the Blake family during the visit, a campaign official told the Washington Post.
President Trump, a Republican, did not meet the family during his own visit to Kenosha on Tuesday, saying he decided not to because of plans to have lawyers attend with the relatives.
Mr Biden's visit to Wisconsin comes four years after the previous Democratic presidential nominee, Hillary Clinton, overlooked the Midwestern state during her campaigning, and it turned out to be pivotal in Mr Trump's against-all-odds 2016 election victory.