The jury in Pontiac, near Detroit, Michigan, cleared Nathaniel Abraham of first-degree murder - a charge that could have exposed him to a life sentence - but nevertheless decided that he was criminally responsible for the death of Ronnie Greene, who was shot in the head outside a convenience store two years ago when Abraham was 11.
Abraham admitted to police that he had been shooting a .22 calibre rifle from a clump of trees across the street, but claimed that the killing was an accident.
His lawyers had argued that he had been shooting at trees when a bullet had ricocheted. However, prosecutors in the case revealed that Abraham had had 22 previous encounters with the law and had boasted to friends that he intended to kill someone.
The controversy arose not over the facts of the case, but over the decision to try someone so young as though he were a fully responsible adult. "Nathaniel Abraham is being tried as an adult, and he can't drive a car, he can't drink, he can't vote, he can't join the military service," said his attorney, Geoff Fieger.
The state of Michigan passed legislation in 1997, shortly before the shooting, allowing children under the age of 14 years to be tried as adults for certain categories of violent crime, including murder.
This was the first test case of the legislation, however, and it has generated an anxious national debate about juvenile justice, particularly as the Abraham trial was broadcast on the Court TV channel and has featured on several high-profile television magazine programmes, such as Sixty Minutes on CBS.
Human rights groups, including Amnesty International, have accused the state of attempting to throw away a young boy's life as if it were "human garbage".
Mr Fieger argued that his client had been denied the basic right to be judged by a jury of his peers, as all 12 jurors were adults. He also pointed to psychological testing that had assessed Abraham as having the mental capacity of a child aged six or seven.