The mother of a boy who was mauled to death by an American XL Bully dog has backed calls to ban the breed and called for tougher prison sentences for owners whose dogs attack people. Emma Whitfield, whose son Jack Lis was 10 years old when he was killed, said: “If Jack was attacked by a Jack Russell or a small dog, I can guarantee you he’d be next to me. But these XL Bullies have got the power to kill.”.