How is it possible for us to have a genetic disease that your grandparents had/have but our parents never had it

Lance, a hacker, stole 15,000 credit card numbers and sold them on the black mar-ket, making millions. police caught lance, and two legal actions followed, one civil and one criminal. who will be responsible for bringing the civil case? what will be the outcome if the jury believes that lance was responsible for identity thefts? who will be responsible for bringing the criminal case? what will be the outcome if the jury believes that lance stole the numbers?