FILE-A police officer pulls police tape at a crime scene. (Aimee Dilger/SOPA Images/LightRocket via Getty Images) MUNCIE, Ind. - A 6-year-old boy fatally shot his 5-year-old sister in their home in eastern Indiana and their parents have been arrested in the killing, police said.First responders discovered the girl with a gunshot wound to the head early Tuesday afternoon at the home in Muncie, 60 miles (100 kilometers) northeast of Indianapolis.