In these last chapters, one can easily see how completely Smerdyakov has planned the homicide. We hear, first of all, that Dmitri has heard of the secret signals by which Grushenka is to come to the old man. There could, of course, be no reason for Smerdyakov to tell Dmitri about these signals except to lay suspicion on Dmitri when it is known that he was aware of such signals; furthermore, Ivan's ready acceptance of Smerdyakov's explanation indicates that Ivan is also eager to accept such an alibi. Second, Smerdyakov announces that he feels that he will have an epileptic seizure on the following day — the day that Ivan will be absent from the house. Third, Smerdyakov announces that old Grigory will be doped with some strong medicine that Marfa gives him and always saves a bit of for herself; soon both will be in a heavy sleep. Consequently, Smerdyakov has conceived a perfect setting for murder; he has even created perfect alibis. As he announces later to Ivan, everything had to go just as he planned it; otherwise, the murder never could have been accomplished. Ivan even recognized this when he said earlier, "But aren't you trying to arrange it so?" and tried to remove himself from direct responsibility. But ultimately Ivan must take his share in the moral guilt for his father's death.
At the end of Book V, most of the machinery is arranged for the murder. Smerdyakov pretends to have his seizure, old Grigory is laid up with illness, Marfa prepares the medicine for them both, and Fyodor anxiously awaits Grushenka.
