The US has seen a wave of protests over the deaths of Michael Brown and Eric Garner, two black men killed by white police officers.
During the demonstrations, activists have highlighted other cases across the US of civilian deaths involving police.
Here are some of the cases they are focusing on.
Freddie Gray - Baltimore, Maryland
Freddie Gray, 25, died in hospital from spinal injuries a week after police took him into custody.
In mobile phone video of the arrest, Gray can be heard screaming repeatedly before a police van arrives to take him away. Police said he "suffered a medical emergency" while in the van.
Gray's lawyer says that his "spine was 80% severed at his neck".
Walter Scott - North Charleston, South Carolina
Walter Lamer Scott, 50, was stopped for having a broken rear light on his car in North Charleston, South Carolina. He was then shot from behind eight times as he ran away from Officer Michael Slager.
Mr Scott died at the scene. The shooting was captured on video and Mr Slager has since been charged with murder.
Eric Harris - Tulsa, Oklahoma
Eric Harris, 44, was chased by police officers then shot as he lay on the ground during an undercover weapons sting. After he was shot, officers continued to subdue him and told him to "shut the [expletive] up" when he complained.
He was treated at the scene but died later in hospital. The volunteer police officer who shot him insists that he had meant to reach for his Taser instead.
Rumain Brisbon - Phoenix, Arizona
Rumain Brisbon, 34, was shot dead by a white police officer this week as he reached into his waistband when instructed to raise his arms, police said. It turned out that he had a pill bottle in his pocket, not a gun. Police in Phoenix, Arizona, said they were investigating drug-related activity at the time.
Tamir Rice - Cleveland, Ohio
Tamir Rice was shot in Cleveland, Ohio, after a 911 caller told police he was pointing a gun at people in a park.
He was 12 years old and the gun was found to be a toy, but the orange sticker denoting it was a replica had been removed.
Darrien Hunt - Saratago Springs, Utah
Darrien Hunt was shot by police officers in Saratoga Springs, Utah, while dressed as a samurai and holding a decorative sword.
The county attorney ruled last month that the killing on 10 September 2014 was 'justified', saying Mr Hunt had "swung or stabbed" the sword towards at least one of the officers. His family and civil rights activists are calling for a review of the findings.
Ezell Ford - Los Angeles
Ezell Ford was shot dead by police in Los Angeles on 11 August after officers said he tried to grab the gun out of an officer's holster. The 25-year-old, who was mentally ill, is said to have tackled the officer, but a witness told the LA Times she saw no such struggle.
Police are looking for more witnesses, while Los Angeles Mayor Eric Garcetti has called for the release of an autopsy report.
Michael Brown - Ferguson, Missouri
Michael Brown was killed by Darren Wilson, a white police officer, on 9 August in the St Louis suburb of Ferguson, Missouri. Mr Wilson said he opened fire after a struggle in the patrol car during which Mr Brown reached for his weapon.
Some said the teenager, who was unarmed, had his hands up. His death sparked protests, sometimes violent, as police were criticised for using military grade riot gear. Further unrest followed a grand jury's decision not to charge Mr Wilson.
Eric Garner - New York
Eric Garner, 43, was stopped on a street in New York on 17 July 2014 on suspicion of selling loose, untaxed cigarettes. After a confrontation, police officer Daniel Pantaleo placed his arm round Mr Garner's neck in an apparent "chokehold".
Mr Garner, who had asthma, was wrestled to the ground and restrained by force. On video of the incident, he can be heard repeatedly saying "I can't breathe". He became unresponsive and later died.
Dontre Hamilton - Milwaukee, Wisconsin
Dontre Hamilton was killed by white police officer Christopher Manney in Milwaukee in April. Mr Hamilton, whose family said he had suffered from schizophrenia, was shot after workers at a Starbucks cafe called police to complain about him sleeping in a park.
According to Mr Manney, Mr Hamilton resisted arrest when he tried to frisk him, and hit him on the neck after the two exchanged punches. Mr Manney then shot him 14 times.
A local prosecutor said he would not bring charges against the officer because Mr Manney had acted in self-defence. The US justice department has said it will review the case.
Trayvon Martin, Sanford, Florida
Trayvon Martin, 17, was shot by George Zimmerman, a neighbourhood watch coordinator, in Sanford, Florida, and was unarmed at the time.
Mr Zimmerman, the man who shot him, was not a police officer, but the killing in February 2012 became particularly controversial due to Mr Zimmerman's eventual acquittal. The case has been cited by numerous commentators in the wake of the deaths of Mr Brown and Mr Garner.
Bernard Bailey, Eutawville, South Carolina
The killing of Bernard Bailey in 2011 came under the spotlight after a white former police chief was charged with his murder on Thursday.
Richards Combs is accused of shooting Mr Bailey, who was unarmed, after a fight outside the town hall in the tiny South Carolina town of Eutawville.