A Gratiot County teenager pleaded guilty on Monday for killing his sister in 2019. 17 year old Corbin James Redman, was accused of shooting and killing his sister, 11-year-old Addison Marie Redman, in their Arcada Township home on Aug. 20, 2019. He was 15 at the time. A designation hearing will be scheduled in April to determine if he should be sentenced as a juvenile or an adult. He faces up to two years in prison if sentenced as an adult.