Unfinished Business

S1, E10: Walt investigates the murder of a teenager who was one of four boys acquitted of raping a developmentally disabled Cheyenne girl. When another boy is killed, all signs point to the crime being an act of revenge by the girl's brother. But Walt is not convinced by the circumstantial evidence and must find the real killer before someone else ends up dead. And the arrival of a detective from Denver forces Walt to finally confront the reality of his wife's death.