A Brooklyn man was convicted on Friday of participating in a racially charged beating of a black college student in fall 2013 that left the victim without vision in his right eye.

Justice Danny K. Chun of State Supreme Court in Brooklyn issued the guilty verdict after a bench trial that included video surveillance footage, DNA evidence and testimony from the victim, Taj Patterson, who described being set upon by up to 20 men as he walked through the Williamsburg section of Brooklyn early one morning.

Appearing before a hushed gallery that was filled to capacity, Justice Chun announced that he found the defendant, Mayer Herskovic, 24, guilty of unlawful imprisonment, menacing and gang assault. The last charge carries a penalty of three and a half to 15 years.

The brutal beating of Mr. Patterson in a primarily Hasidic neighborhood drew comparisons to previous attacks on black men in white ethnic enclaves, like one that occurred three decades ago in Howard Beach, Queens. The assault in Williamsburg also raised questions about the private security forces known as shomrim, a Hebrew term meaning guards, which patrol ultra-Orthodox parts of Brooklyn. While some have said the groups provide a sense of safety, others have said they sometimes act like vigilantes.