David Velazquez, 20, was shot multiple times, the Cook County Medical Examiner's Office said Monday.
The Will County Sheriff's Office received several 911 calls about a large fight on State Line Road in Crete early Sunday.
Deputies said they arrived to find a crowd at a family party, where three had been shot.
The victims were taken to area hospitals, where Velazquez died. The other two victims were in critical condition.
Will County officials said the shooting appeared to be an isolated incident with no further threat to the public.
Sunday morning's shooting followed a week of tragedies for the small town of Crete. The rural community sits on the border of Indiana.
Last Monday, three family members were found dead inside a home. An Indiana woman was charged with first-degree murder.
Early Wednesday morning, a grandfather and his three granddaughters were killed in a massive house fire.
So far, no charges been filed.