Warning: Video contains graphic content that may upset viewers.
Charges won't be laid against the officer who fatally shot Keith Scott in North Carolina earlier this year.
Charlotte officer Brentley Vinson shot Mr Scott four times after police repeatedly told him to drop a gun he was holding.
Mr Scott was backing away and held the gun at his side when Mr Vinson perceived his movements as an "imminent physical threat" and shot him.
Mecklenburg County district attorney Andrew Murray says Mr Vinson "acted lawfully" and "was justified in shooting him".
Fifteen prosecutors unanimously reached the decision not to file charge in the case on Wednesday (local time).
Police were at the scene to arrest someone else when they came across Mr Scott in his car at an apartment complex.
He was using what appeared to be marijuana and had a handgun, which prompted officers to ask him to exit the vehicle.
Initially Mr Scott resisted the order, before exiting his car while holding his gun, slowly backing away from police and ignoring orders to drop the firearm.
Mr Vinson then fired four shots. Mr Murray says he was "fully satisfied" Mr Vinson's use of deadly force was lawful.
"After a thorough review it is my opinion that officer Brentley Vinson acted lawfully when he shot Keith Lamont Scott," Mr Murray said.
"Anyone is justified for using deadly force if they are in danger of great bodily injury or death."
North Carolina is an open carry state, which means citizens can openly display firearms in their possession.
Mr Scott's wife Rakeyia told police her husband had a traumatic brain injury and had just taken his medicine at the time of the incident.
"He's not going to do anything to you guys," she told officers, a video of the event showed.
The shooting kicked off several days of protests, which placed pressure on police to release their own recordings of the incident.
Videos from an officer's body camera and a dashboard camera from inside a police vehicle were released after the Charlotte police chief decided it would not "adversely impact" the investigation.
"What we are releasing are the objective facts," said Chief Kerr Putney, calling the shooting "a complex case".
While it wasn't clear in either the family's or the police's video, Mr Murray says "all the credible evidence" says Mr Scott was armed at the time.
A gun recovered at the scene was found to be loaded with one bullet and had Mr Scott's DNA on the grip and slide.
After Mr Murray's announcement, attorneys for Mr Scott's family said while they appreciate the respect and courtesy Mr Murray and his department have shown the family, they will continue to investigate the incident.
"We still have concerns and it's important for the public to understand that this doesn't end our inquiry," said Charles Monnett, one of the family's attorneys.
"There are differing legal standards that apply to a decision about whether an officer should be criminally charged with the discharge of their weapon in the use of deadly force and whether the department, the officer or the city should be held civilly liability for negligence for the way this situation was handled."
Mr Monnett said the family still has "real questions" about whether the Charlotte officers acted appropriately, including "whether they used appropriate de-escalation techniques to end this situation in a way that didn't end in the loss of Keith Scott's life".
He asked that if anyone protests after the incident, they do so lawfully and peacefully.