The Warden, from the book Holes, is related to Charles and Linda Walker. We are told that the Warden is a direct descendant of those two.
The story of Charles/Trout Walker is a bit convoluted, but I'll try to break it down simply. Charles Walker was in love with a woman named Katherine. Unfortunately for him, Katherine, a white woman, was in love with Sam, a black man. Bigoted Charles and the town wouldn't stand for such a thing, so they drove the couple away. Sam is killed making the escape. Katherine becomes the infamous Kissin' Kate Barlow, a notorious outlaw robber. She never reveals where she buried/hid all of her stolen money even though Charles Walker tried to torture the information out of her. That is why the Warden is obsessed with digging holes. She is attempting to find the money.