Toribio Aldrete is one of Pedro's challengers. He builds a fence trying to show the property line between the Media Luna ranch and his land, and pays dearly for it. Pedro has him killed, even though Toribio is legally right. Like anything being "legally right" ever stopped Pedro, right?
He is hanged in the room where Juan first tries to sleep, and Pedro's men leave him locked in the room so that he won't be buried, and therefore will be kept out of heaven. His screams wake up Juan that first night in Comala.