A six-year-old boy has accidentally shot and killed his three-year-old brother while playing "cops and robbers" with a gun their father told investigators he obtained illegally from a gang member.
Police in Chicago said the two boys were playing when the older one reached on top of a fridge and grabbed the loaded handgun and then accidentally shot three-year-old Eian Santiago in the face.
The boy was rushed to hospital, where he died later.
Police subsequently arrested the boys' father, 25-year-old Michael Santiago, on a felony child endangerment charge. During a court hearing, prosecutor Joseph DiBella said Santiago bought the gun off the street, kept it "wrapped in pyjama pants on top of the refrigerator" and even showed the boy where the gun was.
"He kept the gun for protection because he was a former gang member who snitched on a gang member in a murder trial," the Chicago Tribune reported Mr DiBella as saying in court. Santiago told police about the gun in a videotaped confession, he added.
Judge James Brown set Santiago's bail at 75,000 dollars (£48,000). Santiago was represented by the county public defender's office.
Police Superintendent Garry McCarthy said the case illustrates a point he has been making for years about how a major cause of much of Chicago's violent crime is a flood of illegal guns into the city.
"It's real simple. If that gun is not in the house that kid is alive today. We see this happen over and over and over again."
Mr McCarthy routinely points out that his officers seize many times more illegal guns than any other city in the nation, including the larger cities of New York and Los Angeles. The department has seized more than 5,500 illegal weapons so far this year.
Chicago has more homicides than any other city in the US, and the number this year has climbed, with department statistics showing there were 370 homicides as of October 4, compared with 306 for the same period last year. The number of shooting incidents has climbed during the same period to 1,870 from 1,581.
Some members of the city council recently called for Mr McCarthy to resign because they said he had failed to stem the violence.
But he said that even when people are convicted in Chicago of gun possession, sentences in Illinois are not as long as they should be and dangerous criminals are back on the street within months or even weeks.
"Until something happens with these gun laws, it's going to continue," he said.