A 46-year-old man was shot in the head at around 3:50 a.m. during an event described as an "adult party" at the East 92nd Street location.
The victim, believed to be the DJ working at the event, was taken to the hospital in critical condition.
Three others - a 33-year-old woman and two men, ages 24 and 40 -- were shot in the legs and arrived on their own at Kings County Hospital.
An unknown gunman fled the scene.
It appears the suspect was asked to leave the party being held in a rental hall, and then came back and opened fire.
Detectives are investigating preliminary reports that the man may have been asked to leave for not wearing a face mask.
No arrests have been made.
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