An argument on Tucson’s south-west side led to one man dead Sunday night.

Pima County Sheriff’s deputies responded to an unknown problem in the 5400 block of South Oriole Avenue, near West Irvington Road and South Cardinal Avenue, at just before 7 p.m.

Deputies arrived to find 52-year-old Earl Jackson dead from a gunshot wound and 27-year-old Francisco Fernando Ornelas on the scene, according to a news release from PCSD.

Detectives determined that Jackson and Ornelas were related and had an argument that had turned into a physical fight. During the fight, Ornelas allegedly shot and killed Jackson, according to the news release.

Ornelas was arrested on suspicion of second-degree murder.

The investigation is ongoing.