A man in Chicago has been charged with felony child endangerment after his 6-year-old son shot and killed his 3-year-old brother.

The shooting occurred Saturday night, around 3am Irish time.

The man reportedly sourced the weapon illegally.

Chicago PD spokesman Anthony Guglielmi says that 25-year-old Michael Santiago told investigators that he was a former gang member and felt he needed the gun to protect his family.

Guglielmi says the 6-year-old boy and his younger brother wanted to play "cops and robbers" when the older boy retrieved the loaded handgun from on top of the refrigerator, and subsequently shot his 3-year-old brother.

Santiago is scheduled to appear in court on Sunday and Guglielmi states police are attempting to trace the gun.