Why is the running boy a mystery to Roy in Hoot?

Several things about the running boy intrigue Roy. Roy first sees him when Roy is on the school bus on the way to school. The fact that the boy, who looks to be about Roy's age, is not getting on the school bus like all the other kids seems strange. Another idiosyncrasy is that the boy isn't wearing shoes. In fact, the soles of the boy's feet are "as black as barbecue coals," suggesting that the boy hasn't worn shoes for quite some time and perhaps doesn't bathe regularly. The boy is running very fast, faster than the fastest boy Roy knows, and he's not dressed appropriately for going to school. The boy pays no attention to a German shepherd dog that runs toward him. He jumps over the dog without breaking his stride. Finally, the boy has a very intense look on his face. Roy wonders where the boy can be going, why he's not in school, and why he has such a serious look on his face.