CHICAGO — An 18-year-old man has died after being shot while riding in a vehicle on the city’s Southwest Side.

Police said the shooting happened around 11:15 a.m. Monday in the 5800 block of South Western in Gage Park. The 18-year-old was a passenger in a vehicle when another car approached and someone inside opened fire.

He was shot in the upper back and transported to Holy Cross Hospital, where he was pronounced dead.

The medical examiner has identified the 18-year-old as Robert Santos.

No other injuries were reported.

No one is in custody. Area One detectives are investigating.