Police said the shooting happened around 6:30 p.m. in the 9900-block of Crilly Drive.
Three men, a 25-year-old and two 26-year-olds, were in the park when they started arguing with another person, police said. That person then pulled out a gun and fired shots, striking the men.
All three victims were taken to the University of Chicago Medical Center, where the 25-year-old died, and the 26-year-olds are in critical condition.
Investigators recovered a gun from the scene.
No one is in custody.
Police did not immediately provide further information about the shooting.
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