NYPD Detectives from the 60th Precinct and members of the Violent Fugitive Task Force arrested 29 year-old Joseph Brown at 6 a.m. Saturday.
Police say he was apprehended at an apartment close to the shooting scene.
The shooting happened Friday inside apartment 5B at 2703 West 33 Street in Coney Island around 3:30 p.m.
A man was shot in the head and pronounced dead at the scene.
A 24-year-old man was shot in the head and is listed in critical condition. A 40-year-old man suffered a graze wound to the head and was treated on the scene.
A 62-year-old grandmother was shot in the stomach and taken to Lutheran Hospital where she is in critical condition.
A preliminary investigation determined that Brown entered the apartment and shot the victims.
The suspect's motive is under investigation.