Prosecutors say 22-year-old Brandon Upshaw buried a .45-caliber handgun in the backyard of his family home in suburban Dolton.
On Tuesday, authorities say, his 11-year-old brother found the gun and accidently shot and killed 8-year-old Kyree Davis.
Upshaw faces several charges, including child endangerment and unlawful possession of a firearm.
He was released on an I-bond.