Priest uncredited 1 episode, Tarla Grant 2 episodes, Lumen Pierce is first seen after witnessing Dexter kill Boyd Fowler, a serial killer who had been keeping her captive. While Dexter suspects that Jonah was the perpetrator, with evidence supporting, Jonah's guilt emerges in a confrontation which shows that he killed his mother for instigating his sister's suicide. Congenial Narrator 1 episode,
She frequents support groups to observe the emotions that she is incapable of feeling.
Newly promoted to the homicide department, Debra's first case is a series of murders committed by "The Ice Truck Killer", who preys on prostitutes and leaves their dismembered bodies in refrigerated trucks. In the season 4 finale, he is seen being taken out of his home by the police when they uncover that Arthur is Trinity. LaGuerta used the information on Tom and betrayed him and had him forcibly retired by the board when she told them. As the season progresses, particularly after his encounter with Dexter, Travis begins to feel guilty about the suffering of their victims despite Gellar's insistence that the victims are sinners and their deaths are necessary. After searching Brian's apartment, Dexter tracked him down at the site of their childhood home, where Dexter recalled that they were brothers. As a result of this, Captain Matthews becomes increasingly concerned that he had made the wrong decision in replacing LaGuerta with Pascal, but LaGuerta remains stalwart, apparently standing behind Pascal on principle of loyalty.