Protesters in California closed part of a motorway as they marched over the fatal shooting of an unarmed black man in Sacramento.
Hundreds of people rallied after the death of Stephon Clark, a 22-year-old who was shot on Sunday in the back garden of his grandparents' home.
Police said they feared he had a handgun when they confronted him after reports that he had been breaking windows in the south Sacramento neighbourhood.
But police found only a mobile phone.
"We are at a place of deep pain" because of recent violence directed at black people in Sacramento and elsewhere, said the Rev Les Simmons, a community leader.
He said the city's first black police chief, Daniel Hahn, is doing what he can but protested over the actions of Mr Hahn's officers.
Clinton Primm said he was friends with Mr Clark, who was nicknamed Zoe, for about six years and fears others are also at risk of being shot by police.
"He was a great dad," he recalled of Mr Clark, the father of sons aged one and three. "He loved both of them to death."
Sacramento resident Vanessa Cullars said she has lost two family members to police violence.
"I'm fed up with this," she said at the protest. "I feel like our lives don't matter to them."
Sacramento mayor Darrell Steinberg said he was horrified by the death but would not second-guess the "split-second decisions" of the officers.
He praised Mr Hahn for quickly releasing videos of the shooting and said the department has improved its policies since the fatal shooting of a mentally ill black man in 2016.
But independent experts said the footage from body cameras and an overhead helicopter raises more questions than it answers.
The officers appeared to believe they were in danger, they said, and if so the shooting was likely to be legally justified.
One officer is heard "doing a mental inventory to make sure there's no holes in his body" because the officers appear to think Mr Clark may have shot at them and missed, said Peter Moskos, a former police officer and assistant professor in the Department of Law and Police Science at John Jay College of Criminal Justice.
But Geoffrey Alpert, a professor of criminology at the University of South Carolina and an expert on police use of force, said the officers may have a difficult time explaining why they jumped to the conclusion that Mr Clark had a gun.
He also questioned why an arriving backup officer had the two original officers turn off the microphones on their body cameras, eliminating what he called "important evidence".
In an ideal world, the two officers should have immediately provided first aid instead of waiting five minutes for backup, said Eugene O'Donnell, a professor of police studies at John Jay College of Criminal Justice.
"But that could be more the product of hope than reality," he said, with the officers still in shock and worried about their own safety.
The Sacramento Police Department said officers were responding to reports of a man seen breaking into at least three vehicles and later into a neighbour's home.
The police said deputies in the helicopter saw Mr Clark break a neighbour's sliding glass door before jumping over a fence.
As a result "their threat radar is really high", said Plumas County sheriff's deputy and special prosecutor Ed Obayashi, who trains officers and gives evidence in court on police use of force.
"They have to assume that their lives are in danger at that very second," he said.