Police said they were called to the scene around 6:55 a.m. after reports of shots fired inside the gambling location, which was also described as a social club, at 74 Utica Ave.
Four men were killed and three people wounded early on Saturday in a shooting at an unlicensed gambling club in New York City, police said. Two may live out of state and the rest live in neighborhoods throughout Brooklyn.
Chief of Detectives Dermot F. Shea said at a press conference several hours after the shooting that at least two firearms - a 9mm handgun and a revolver - were recovered from the scene. Investigators say at least 15 shots were fired. They were said to be between the ages of 32 and 49.
The four male victims were pronounced dead at the scene, police said.
Three wounded people were taken to hospitals with injuries that were not life-threatening, Shea said.
Chief of Patrol Rodney K. Harrison said there were never any complaints of a gambling operation at the location, which was only a few blocks away from the 77th precinct.
No arrests have been made and police do not know the motive for the shootings, The NYPD official said.
Crown Heights has seen a rash of gang-related shootings this year, the New York Times reported.
The shooting was the second mass killing in NY in a week in a city that has seen a marked drop in homicides in recent years. Four homeless men were beaten to death, allegedly by another homeless man, on October 5 in Manhattan's Chinatown.
Mayor Bill de Blasio, a Democrat, said on Twitter that the city "awoke to senseless gun violence".