Jonathon Williams, 20, was killed, and 19-year-old Darius Bell was also shot. Bell was in critical condition Sunday evening.
Although few details have been released, a woman at the bar described to ABC7 Chicago what she saw happen.
"We was all dancing, having a good time. Next thing I know, people just started fighting. They went outside. We heard gunshots. They came back inside the club. Soon everybody was just running every which way trying to get out, trying to get safe," Natashia Dedrick said.
No one was in custody Sunday night. The Chicago Heights police and the South Suburban Major Crimes Task Force are investigating the shooting.