 Harper and Graves retrieve the money and Graves drives Harper home.On the way, Harper tells Graves he knows he is the fourth man, because the locker key is still in Harper's pocket and a kidnapper would have searched him for it while he was unconscious.Graves admits he killed Sampson, saying he did so because Sampson was a monster who was cruel to everyone, including him, when he prodded Graves to pursue Miranda's affections just for his own cruel amusement.