Witnesses told police there was a fight between two females in a parking lot at 631 Lakehurst Road in Waukegan. Mieshon Harvey, 21, tried to stop the fight when 24-year-old Josiah Mars got into an argument with him, police said.
During the altercation, Mars got a handgun from 32-year-old Derrick Wells and shot Harvey in the chest, police said.
Harvey died shortly after arriving at Vista East Hospital, according to the Lake County Coroner's Office.
Both Mars and Wells fled the scene but were later arrested by Waukegan police. Mars was in possession of a handgun that matched the caliber of the gun used in the shooting, police said.
The firearm has been sent to the crime lab for additional testing.
Mars and Wells were each charged with three counts of murder. Wells was also charged with aggravated domestic battery and two counts of domestic battery.
Both suspects were ordered held at the Lake County Jail on a $5 million bond.