Thirty-nine-year-old Bonnell Hanger was charged Thursday with first-degree intentional homicide.
According to the complaint, Hanger cried before telling police, "I shot my kid brother."
Witnesses say Hanger and his 33-year-old brother, Fredica Hanger, had argued before the shooting Monday night on Madison's Near East Side.
The complaint says Fredrica Hanger was in his car installing a car stereo when his brother arrived. The two argued, and Fredrica Hanger was shot. He was pronounced dead at UW Hospital.
The Dane County medical examiner says Fredrica Hanger died from gunshot wounds to the head.
Bonnell Hanger surrendered to police at the scene. The Wisconsin State Journal reports he was jailed on $100,000 bail after appearing in court.