PHOENIX -- A 45-year-old man is dead after police said a gunman opened fire at Sterling Point Apartments at 38th Street and Baseline Road.

The name of the victim has not yet been released.

Officers said a man walked up to the victim’s first-floor apartment around 11 p.m. and knocked on the door.

When the apartment dweller answered the door, four shots rang out, police said.

The victim’s sister and mother were inside the apartment and not harmed.

Police are trying to determine a motive for the shooting.