A 43-year-old man was fatally shot inside a Brooklyn apartment building on Thursday night, police said.

The victim was shot to the torso inside the building on Bay Parkway near West 12th Street in Bensonhurst at about 11:30 p.m., according to cops.

The victim — who does not live in the building — was found on the stairwell between the second and third floors, authorities said. 

Three people fled the scene after the shooting in a four-door sedan heading south on Bay Parkway, cops said.

The man — whose name was not immediately released pending family notification — was taken to Maimonides Medical Center, where he was pronounced dead, authorities said.

No arrests were immediately made.