Atlanta police homicide Det. Lt. Keith Meadows said Rochelle Phillips, who was wheelchair-bound, died at the scene.
He said her 79-year-old husband is also suspected of shooting his stepson in the back of the neck when the younger man came home and tried to wrestle the gun away.
Meadows told the Atlanta Journal-Constitution the man confessed to police and was taken into custody. The stepson is in critical condition at a nearby hospital.