Police said officers responded to gunshot detection technology at Jackson Park in the 2000-block of East 67th Street just before 2 p.m.
Someone approached two men there before taking out a gun and firing shots, police said.
A 39-year-old man, shot multiple times in his body, was transported to the University of Chicago Medical Center, where he was pronounced dead.
Another man, 25, was shot in his shoulder, facial area and thigh. He was taken to the same hospital in fair condition.
No one is in custody and area detectives are investigating.
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