Assistant Public Defender Jon Helland says 39-year-old Bonnell Hanger was afraid of his 33-year-old brother, Fredrica, who had just been released from prison.
The Wisconsin State Journal reports because Bonnell Hanger expressed fear about his brother, prosecutors agreed to let Hanger plead guilty to second-degree intentional homicide.
Hanger will be sentenced in Dane County in about two months.
According to the complaint, witnesses say Fredrica Hanger was in the driver's seat of a car, parked outside his mother's home, installing a car stereo. Bonnell Hanger arrived and knocked on the driver's window, and an argument ensued. Bonnell Hanger pulled out a gun and shot his brother twice in the head.