It happened at the Nostrand Houses in the Sheepshead Bay section around 5:45 a.m.
The 25-year-old Ciera Glenn victim was found dead after being shot in the leg and stomach.
The 27-year-old male victim was shot in the face and rushed to Coney Island Hospital in critical condition.
It's believed that they were attending a Halloween party in the building.
So far, no arrests have been made.