"I do not believe an officer did anything wrong," Harrell said. "The entire time, the victim is being attended to without delay."
Koser, a junior at Alpharetta High School, died at the scene. He was shot at close range, police said.
Brandon, 46, is charged with two counts of felony murder and with possession of a weapon while committing a felony. He is in Fulton County Jail. A bond hearing is scheduled for Feb. 27.
--Staff writer Marcus K. Garner and photographer John Spink contributed to this report.