Hudson County Prosecutor Edward DeFazio says the shooting occurred just before midnight Friday, when police responded to calls about a large disturbance.
Shortly after they arrived, Jermaine Williams of Jersey City was shot at least once in the abdomen and apparently jumped into the river. Authorities then began an immediate search, but the body wasn't found until just before 3 a.m. Saturday.
DeFazio said it's not clear whether Williams died from the gunshot wound or drowned. An autopsy was to be performed later Saturday. He said the case was considered a homicide, though it's not yet known who fired the shot that hit Williams.