The 16-year-old was pronounced dead about 90 minutes later at Northwestern Memorial Hospital, according to authorities.



The two boys had been arguing earlier about an Xbox, according to a police report.



A fired 9mm cartridge was found in the teen's bedroom and a 9mm semi-automatic handgun was recovered in the apartment, said Tandra Simonton, a spokeswoman for the Cook County State's Attorney's Office.



The 13-year-old told police he shot Galloway, she said. Police said the boy's mother was present when he made that statement.



The boy was charged as a juvenile with first-degree murder just after midnight Monday. Judge Stuart Katz ordered him held in custody, Simonton said.



It's not clear where the boy got the gun. No adults have been charged.



Galloway lived in the 4300 block of South Champlain Avenue, a spokeswoman for the Cook County medical examiner's office said.