Just after midnight on May 12, 2006, a man woke up in his quiet London suburb to the sound of pounding on his front door. He answered it and found his neighbor standing outside, looking shocked. The neighbor said something had happened to the man’s sister. The man immediately ran down the street, towards his sister’s house. He was afraid of what he’d find, because he was always warning her to be more careful, but she never listened. And when he arrived, he found a trail of blood running down his sister's driveway.