A Chicago man was fatally shot during a domestic incident Sunday morning in south suburban Oak Forest.

Officers responded to a domestic disturbance with shots fired in the 6600 block of 157th Street about 9:25 a.m. They found 21-year-old Adrian R. Gagen lying unresponsive in a driveway, according to Oak Forest police and the Cook County medical examiner’s office.

Gagen, a South Side Chicago resident, was taken to South Suburban Hospital in Hazel Crest, where he was pronounced dead at 10:20 a.m., according to police and the medical examiner’s office. An autopsy found he died of a gunshot wound to the back, and his death was ruled a homicide.

Police said the shooting stemmed from a dispute between family members.

A person of interest was taken into custody, but Police Chief Tim Kristin said Wednesday that person has been released without being charged.

The South Suburban Major Crimes Task Force is investigating along with Oak Forest police.