looking for a story

Story about a brother and sister brother was always pick on at school so as they got older sister was getting tired of it so much that one day as the two of them was driving home she saw them she ran them over the brother loving his sister so much took the blame for it they found him guilty. Ended up on death row. The government knew he was innocent but had to make it look good they turn him into a girl. Hope some one remembers the story thank you.