Police released two videos showing an officer fatally shooting an unarmed black man in a San Diego suburb and said they hoped showing the footage would ease escalating tensions.
The videos show the officer fired four times at close range almost immediately after Alfred Olango, 38, suddenly raised both hands to chest level and took what was described as a shooting stance.
The shots came less than a minute after police arrived at the scene in response to Mr Olango's sister calling 911 and reporting he was acting erratically.
The videos were released after three nights of unruly and, at times, violent protests in El Cajon, and on the eve of a demonstration organised by clergy and supporters of Mr Olango's family, who had pressured authorities to show the footage of the fatal encounter.
On Thursday night, an officer was struck in the head by a brick hurled by a protester.
"Our only concern at this point was community safety," police Chief Jeff Davis said.
"We felt that the aggression of some - some - of the protesters was escalating to the point where it was necessary to release some information and truly, it was my hope to relieve some of that concern."
The Rev Shane Harris of the civil rights organisation National Action Network said the low-quality videos, shot at a distance, did not clarify what led to the shooting and warned that they are likely to make people angrier.
He said: "What we saw today, that isn't enough."
In addition to the videos, police showed the four-inch electronic cigarette device Mr Olango had in his hands when he was shot.
A lawyer for the family said they welcomed the release of the videos, but he questioned the tactics used by Officer Richard Gonsalves.
Mr Olango had been reported to be mentally disturbed and unarmed and yet the officer approached with his weapon out, Dan Gilleon said.
"It shows a cowboy with his gun drawn provoking a mentally disturbed person," Mr Gilleon said.
The incident is the latest in a series of fatal shootings of black men in communities across the US, including in Tulsa, Oklahoma, and Charlotte, North Carolina.
Olango, a Ugandan refugee who arrived in the US as a boy, had a criminal record that included drug and weapon charges but no violence.
His family described him as a loving father and a joyful, happy person. His mother said he suffered a mental breakdown recently after the death of his best friend.
On Tuesday, his sister called 911 and reported he was acting strangely and walking into traffic by a shopping mall.
The longer of the two videos released by police came from a surveillance camera in a drive-through restaurant. It is roughly a minute, has no sound and police blurred out the heads of everyone in it.
Mr Olango is seen walking through the car park and then stopping suddenly as Mr Gonsalves approached, his weapon drawn at his side.
Mr Olango, his right hand in his trouser pocket, moved side to side and backed up towards a white pick-up truck.
In the second video, taken on a mobile phone by a witness in the drive-through, Mr Olango's sister is seen approaching Mr Gonsalves from behind and a woman can be heard screaming at Mr Olango to put up his hands and telling police not to shoot.
Mr Olango then bent over and assumed the shooting stance and Mr Gonsalves quickly fired four shots at close-range. A woman shrieked loudly as Mr Olango fell forward.
That night, as an angry crowd protested outside police headquarters, Mr Davis released a single image from the video showing Mr Olango with his hands clasped in front and in the shooting stance. Police said he had ignored repeated orders to show his hands.
Mr Davis defended the release and said it was intended to de-escalate tensions and correct what he felt was a "false narrative" that was developing.
Some witnesses said Mr Olango had his hands in the air and was begging not to be shot.