 After a game of one-upmanship with regard to Ellen Wolf's murder case, with Miguel threatening to expose Debra Morgan's relationship with the CI Anton and use his position as ADA to make trouble for Dexter, Dexter decides to kill Miguel using the MO ("Modus Operandi") of a sought-for killer, just as LaGuerta discovers Miguel killed Ellen.When Miguel discovers that LaGuerta is investigating him, he plans to kill her.However, Dexter discovers what Miguel is planning, traps him at LaGuerta's house when Prado goes there to kill her, and kills Miguel by garroting him, but not before telling him that he killed his brother.