CHICAGO (REUTERS) - A Chicago man charged with felony child endangerment after his six-year-old son fatally shot his three-year-old brother while playing "cops and robbers," appeared briefly in court on Friday, officials said.

The older boy, whose name was withheld, found a loaded revolver on top of a refrigerator and shot little brother Eian Santiago on Saturday while their father was at work, police and the Cook County Medical Examiner's office said.

The father, Michael Santiago, 25, told police he was a former street gang member and bought the gun from a gang member for protection.

He had testified for the prosecution in a murder trial of another gang member, according to local media reports.

Santiago did not enter a plea during the brief hearing and his next court date was set for Nov 9, according to the Cook County State's Attorney's office.

Santiago, who is free on bond, faces up to five years in prison if convicted.

When the shooting happened, the boys were in the care of their grandfather while their father was at work and their mother at a store.

"Both Michael and Angelita are devastated and are struggling to cope with the death of their son," Santiago's attorneys said in a statement.

"They are facing something no parent would want to face."