Two outside expert reports conducted for the prosecutor in the Tamir Rice case find Cleveland police officer Timothy Loehmann justified in shooting the 12-year-old boy last November.
The white police officer shot dead the black boy who was carrying a toy gun.
The experts’ conclusions come ahead of an expected decision by a grand jury on whether criminal charges are warranted.
In June, a judge ruled Officer Timothy Loehmann should be charged with murder.
Tamir Rice’s family lawyer Subodh Chandra accused the experts of assisting in a “whitewash” of the incident.
The boy was shown on CCTV waving a pellet gun outside a recreation center last November, before being shot twice.
Retired FBI agent Kimberly Crawford, in a review of the shooting, wrote that “not only was Officer [Timothy] Loehmann required to make a split-second decision, but also that his response was a reasonable one”.
The officer “had no information to suggest the weapon was anything but a real handgun, and the speed with which the confrontation progressed would not give the officer time to focus on the weapon”, she wrote.
In another report, Colorado prosecutor Lamar Sims also concluded that “Officer Loehmann’s belief that Rice posed a threat of serious physical harm or death was objectively reasonable, as was his response to that perceived threat”.
Cuyahoga County Prosecutor Timothy McGinty said in a statement his office – which commissioned the expert reports – was not reaching any conclusions based on them.
In June, Judge Ron Adrine said there were sufficient grounds to prosecute Officer Timothy Loehmann with murder, manslaughter and reckless homicide.
Police have maintained that Tamir Rice’s pellet gun looked real and that they asked him to raise his hands three times.
However, Tamir Rice’s family said video footage shows the police acted too quickly after arriving at the scene.
Tamir Rice’s death sparked protests in Cleveland, at a time when the deaths of black men at the hands of police had sparked a national debate.