John Vento, once considered a key witness to the 1989 killing of a black teenager by a mob of white men in Brooklyn, was cleared Thursday of murder and manslaughter charges in the youth's death.

The 22-year-old defendant, who was found guilty on a lesser charge of rioting, was the fourth young man acquitted of murder in the Aug. 23, 1989, killing of 16-year-old Yusuf Hawkins.It was the second trial for Vento in Hawkins' death. In early July, a jury convicted him of unlawful imprisonment, menacing and intentional murder but announced that it was deadlocked on a second murder count as well as the manslaughter and riot charges.