Joliet police were called to the area of Chicago Street and 5th Avenue at about 12:49 a.m. after a report of a person slumped over at the wheel of an SUV.
Officers found the vehicle with two men, 45-year-old Tracy Williams and 53-year-old Bernard Marble, from Joliet inside with gunshot wounds.
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Williams was pronounced dead at the scene. Marble was transported to St. Joseph Medical Center, where he later died.
Joliet police said 41-year-old Tommie McDonald was inside the vehicle with the two victims and he shot them after getting into an argument. McDonald fled the scene before officers arrived but was located in the 200-block of Mississippi Avenue, police said.
Investigators said McDonald made statements indicated his involvement in the shooting. The gun that police believe was used in the shooting was located at the scene.
McDonald has been charged with two counts homicide.