"'When my sister was six years old, she was attacked, set upon, by three Muggle boys. They'd seen her doing magic, spying through the back garden hedge: She was a kid, she couldn't control it, no witch or wizard can at that age. What they saw scared them, I expect... It destroyed her, what they did: She was never right again. She wouldn't use magic, but she couldn't get rid of it; it turned inward and drove her mad.'"