Police said that the woman was shot in Dolton on Saturday and declared dead at a hospital.
Police said that the family was sitting outside a Food 4 Less shop when the boy found the gun and shot it at his mother. After indicating that the gun belonged to him, authorities said that the father of the boy was taken into custody.
The Chicago Sun-Times identified the victim as Dejah Bennet, 22 years old.
Police are still investigating and have not filed any charges. The Associated Press left a Monday message requesting updated information from the police.
Andrew Holmes, Dolton trustee, said Sunday that this could have been avoided. Holmes visited the supermarket to distribute gun locks and talk to customers about gun safety. Holmes explained that it only takes a second to unlock the gun, thread it through a barrel, turn it around and put it in, then lock it.
According to data from advocacy group Everytown for Gun Safety there have been at most 43 unintentional shots by children in the U.S. this year, resulting in 16 deaths, and 29 injuries.
According to the group, there were at most 379 unintentional shots by children last year that resulted in 154 deaths and 244 injury.
