sentences:  Thurlow challenges Robert to a duel, using revolvers from which the bullets have been carefully extracted but, when the duel is fought, Robert is shot dead because the bullets have been returned to the gun.Next, his twin Maclyn is shot in his bed, and the body is found with whip marks on his face next to a dish of broth.As Ellery postulates that the murders are somehow tied to the nursery rhyme, the next death is that of the Old Woman herself.