When five Orthodox Jewish men were accused of beating — and partially blinding — a young black fashion student four years ago in Brooklyn, it briefly reignited one of New York City’s most incendiary racial divides: the one between the borough’s Hasidic and African-American communities.

The case became even more contentious when the prosecutors suddenly dropped their charges against two of the defendants and let the other two plead guilty to lesser crimes, avoiding time in prison. Only one man, Mayer Herskovic, was ultimately convicted at trial and sentenced to state prison.

But in a sweeping decision issued Wednesday, a state appeals court overturned Mr. Herskovic’s guilty verdict and threw out his indictment, saying there was simply not enough evidence to convict him, or to charge him in the first place.

In their decision, the appellate judges noted that the victim of the beating, Taj Patterson, had failed to identify his assailants and that the DNA evidence that prosecutors used to convict Mr. Herskovic was “less than convincing.”