A 23-year-old man was fatally shot Monday evening by a 58-year-old man he was trying to rob in the West Side Austin neighborhood.

Shaquille Gales, 23, of Bellwood, walked up to the older man about 5:45 p.m. in the 5500 block of West Thomas Street, pulled out a gun and demanded his property, according to Chicago Police and the Cook County Medical Examiner’s Office.

The 58-year-old, a concealed-carry permit holder, pulled out his own weapon and shot the attempted robber, police said.

Gales was taken to West Suburban Medical in Oak Park, where he was pronounced dead, authorities said.

An autopsy Tuesday found Gales died from a gunshot wound to the chest through his arm, according to the medical examiner’s office. His death was ruled a homicide. Police initially reported that Gales was shot in the back of the head.

A weapon was recovered at the scene, police said.