Dexter Episode 42: If I Had a Hammer

Dexter intensifies his effort to identify the Trinity Killer while trying to stay ahead of Miami Metro’s investigation, and he also gets pulled into marriage counseling with Rita because of the strain in their relationship.

He begins by tracking Trinity’s routine and learns that the man he has been watching presents himself as **Arthur Mitchell**: a respected high school teacher, church deacon, husband, father, and organizer with the **Four Walls One Heart** homebuilding charity. Dexter is unsettled by how ordinary and affectionate Arthur seems with his family, which makes him even more determined to get close to him and understand how he hides his crimes.

As the police investigate a killing connected to Trinity, Dexter realizes Miami Metro is likely to connect the case to Arthur soon, so he works faster to stay ahead of them. He also follows up on forensic clues from the murder, including evidence that points him toward Arthur’s background and family history. Dexter finds that Arthur’s sister, mother, and father all died in ways that echo the pattern he has been investigating, which strengthens his suspicion that Arthur’s personal history is tied to the killings.

To gain access, Dexter uses the alias **Kyle Butler** and approaches Arthur through the charity work, volunteering with the organization and asking for help by pretending his wife has kicked him out. That gets him closer to Arthur and eventually into his house, where Dexter looks for more evidence and notices an urn containing Arthur’s sister’s ashes; Arthur becomes visibly angry when Dexter touches it. Arthur then apologizes and speaks about his sister as a part of his life, suggesting that his family kept him from a darker path.

At home, Rita is frustrated with Dexter’s lies and emotional distance, so she insists on marriage counseling. In therapy, Dexter initially struggles to explain his behavior, but after reflecting on Arthur’s apparent openness with his own life, he tells Rita that he needs some space for himself. The session leaves the relationship unresolved, but it gives Dexter a new way to present himself without fully revealing the truth.

Meanwhile, Debra is desperate to stay involved in the Lundy case and is angry when she is shut out of the investigation. She believes Nikki Wald is responsible and wants to testify, even though others try to stop her from crossing professional lines. By the end of the episode, Debra is still pushing to keep the case from going unsolved.