Prosecutors in the U.S. city of St. Louis have said they will not file charges against a former police officer who shot dead a young black man in 2014.
The murder of Michael Brown in Ferguson has sparked weeks of protests.
This also led to the founding of the Black Lives Matter movement.
Prosecutors said a five-month re-examination of the case did not find enough evidence to bring charges of murder or manslaughter against former officer Darren Wilson.
In 2015 the Justice Department concluded that he had fired in self-defense.
Why was Michael Brown killed?
The exact details of what happened that day remain disputed by police, eyewitnesses and family members.
What is known for sure is that around noon on 9 August 2014, Mr Wilson was driving a police car and met Mr Brown and a friend walking down the street.
- Who was Michael Brown?
- How one shooting sparked national protests
A minute after 18-year-old Mr. Brown was dead, he suffered at least seven gunshot wounds, according to county prosecutor Bob McCulloch. His body was on the road for four hours before being removed.
Mr Wilson fired a total of 12 bullets, although investigators were unclear how many of those 12 hit Mr Brown. One injury may have been a re-entry injury.
Witnesses said Mr. Brown had his hands on him when he was killed, but investigators said evidence suggested this was not the case.
National protests had sparked the killings and the decision not to charge the officer with murder. Two police officers were shot as riots erupted from Ferguson.
What is the latter?
The findings following a re-examination of the case found, once again, that Mr Wilson should not be charged.
“Can we prove beyond a reasonable doubt that a crime has occurred?” A new prosecutor, Wesley Bell, said at a press conference. “The answer to that is no.”
However, Mr Bell said the investigation could not exonerate the officer, who resigned shortly after the murder.
“There are so many points at which Darren Wilson could have handled the situation differently, and if he had, Michael Brown could still be alive,” he said.
The announcement comes as protests against racism and police brutality continue after the death of George Floyd, an unarmed black man, in Minneapolis, Minnesota, in May.