The incident happened around 10 p.m., when, according to police, two Jet Skis collided, throwing four people - two men and two women - into the water.
The 3,000 residents stood outside for hours as officers searched for drugs and weapons.
The victim, 44-year-old Sandra Serrano, was shot in her face and back, when a man opened fire on an impromptu celebration on a soccer field around 3:30 a.m. on Monday.
Police say a 24-year-old man was stabbed in the neck with an object.
Police say the two men got into a fight and one stabbed the other in the chest.
All shuttles and roadways leading to the Randall's Island venue were shut down.