A grand jury has declined to bring criminal charges against two Cleveland police officers involved in the fatal shooting of 12-year old Tamir Rice.

"Simply put, given this perfect storm of human error, mistakes and miscommunications by all involved that day, the evidence did not indicate criminal conduct by police," Cuyahoga County prosecutor Timothy McGinty told reporters.

The grand jury has been hearing testimony since October about the fatal shooting of Tamir by police last year. It was deciding whether to indict Timothy Loehmann — the officer who shot Tamir — and his partner, Frank Garmback.

Tamir was playing with an air gun in a public park last year when someone called the police. The caller mentioned the gun might be fake, NPR's Nick Castele reported. But "the dispatcher didn't relay the caller's doubts," and "within seconds Officer Timothy Loehmann stepped out of the passenger side and fired two shots, striking Tamir once in the abdomen."

Elle Hearns, the coordinator for Black Lives Matter in Cleveland, told NPR's Audie Cornish that the decision not to indict was "devastating" for the family "who have consistently made requests for support and also for accountability in the murder of Tamir."

She also said, "It's a very somber day here in Cleveland and it's also a really disappointing day for a family, for the city, for activists in a community throughout the country who have consistently advocated for children, for people to be safe in this country."

In explaining the decision, McGinty added that a recent enhancement of the surveillance video was "perhaps the most critical piece of evidence." He said that because of that new enhancement, "it is now indisputable that Tamir was drawing his gun from his waist as the police car slid toward him and Officer Loehmann exited the car." Here's more from McGinty:

"At the point where they suddenly came together, both Tamir and the rookie officer were no doubt frightened. If we put ourselves in the victim's shoes, as prosecutors and detectives try to do, it is likely that Tamir, whose size made him look much older and who had been warned that his pellet gun might get him into trouble that day, either intended to hand it over to the officers or show them that it wasn't a real gun. But there was no way for the officers to know that, because they saw the events unfolding in front of them from a very different perspective."

Hearns, of Black Lives Matter, said the lack of accountability would "fuel the movement."

"When our children's lives are taken and there's no accountability for anyone, that actually is something that will continue to fuel the movement," she said. "There's no trust that the people could ever have for a city that is willing to stand behind officers who are killing their kids."

The incident took place more than 400 days ago. Tamir Rice's family has grown increasingly frustrated with what it sees as the slow pace of justice, as NPR previously reported.

Family members released a statement Monday through their lawyer, accusing McGinty of "abusing and manipulating the grand jury process to orchestrate a vote against indictment," the Associated Press reported.

The family had called for the prosecutor to step down from the investigation. In October, the family accused the prosecutor of "working diligently to ensure that there is no indictment and no accountability."

As NPR's Carrie Johnson reports, federal officials are still on the case. The U.S. attorney for the Northern District of Ohio and the U.S. Justice Department's Civil Rights Division said in a statement after the decision that they are continuing their review of the death.

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