Dexter: Every Character Who Knew About His Dark Passenger (& How They Found Out)

Although Dexter Morgan’s primary rule was to not get caught, several of Dexter’s characters found out about his dark passengers over the course of the series. Dexter documents the life of Dexter Morgan, a vigilante serial killer who also happens to be the blood-spatter analyst for the Miami Metro Police Department. Dexter operates his serial killing unconventionally, sticking to a strict code where he can only kill those who are deserving, confirmed murderers that have evaded the justice system.

While trying to appease his dark passenger’s need for blood, Dexter has to carefully avoid getting caught while on the hunt and after he kills. His most important rule while serial killing is to not be caught, which means not letting anyone know his real identity or being suspicious to those around him. Working for the police station as a blood-spatter analyst helped as a cover-up for many of Dexter’s slip-ups, but it was inevitable that certain acquaintances and loved ones discovered his affinity for killing along the way.

Aside from his plenty of victims that obviously Dexter was a dangerous killer once they were put on his table, only a select few established characters found out about Dexter after meeting him. Here’s a breakdown of all the characters on Dexter who knew about his dark passenger and how they each one found out.

Harry Morgan

Harry Morgan was the first person to discover Dexter’s dark passenger. After finding him in a pool of his mother’s blood in a shipping container, police officer Harry Morgan adopted Morgan as his own son. As Dexter grew older, Harry noticed abnormalities about his son, especially his interest in blood, withdrawn demeanor, and need to kill animals. Realizing Dexter would either need to be institutionalized or likely end up in prison for homicide, Harry decided to use Dexter’s killer affinity for good. Once Dexter killed his first human being (an evil nurse), Harry gave Dexter the “Code of Harry,” which outlined Dexter’s rules for killing, including not getting caught and only killing murderers who escape justice. During this time, Harry had been seeing a therapist who helped “create” Dexter into the vigilante he was, before it all became too heavy of a burden. After physically seeing Dexter murder and chop up one of his victims, Harry became physically sick. Knowing what he created in Dexter and what he had seen, Harry Morgan ended up committing suicide.

Debra Morgan

One of the last characters who discovered Dexter’s dark passenger on the original series, Deb learned Dexter and Harry had hidden his serial killing from her all her life. Even as an adult when Debra was Dexter’s closest connection, he could never tell her because he didn’t want to burden her with the knowledge and figured that, as a cop, she would feel the need to turn him in. Finally, in Dexter’s season 6 finale, Debra happened upon Dexter murdering The Doomsday Killer in his ritualistic fashion at the church. At first, Deb didn’t know he was a killer and only tried to help cover up his apparent one-time murder. As season 7 progressed, Debra found out that Dexter was a methodical serial killer and that their father helped guide him, causing her to be physically ill. Because Deb loves Dexter so much, she still helps hide his identity, even when it leads her to make the life-altering decision of killing Maria LaGuerta.

Brian Moser (Ice Truck Killer)

Aside from Harry, Brian Moser was the first character who revealed he knew Dexter Morgan was a serial killer. He was first introduced as Dexter season 1’s villain, the Ice Truck Killer, under a different alias before explaining he’s actually Dexter’s biological older brother. Brian was also in the shipping container when their mother was murdered, but Harry only adopted Dexter. He kept tabs on Dexter and discovered his younger brother had also developed an affinity for blood and killing, leading Brian to track down Dexter and taunt him with crime scenes and images of their traumatic past. After discovering how dangerous Brian was and that he nearly killed Dexter’s sister Deb, Dexter decided to put him down, though Brian’s legacy haunted him throughout the series.

James Doakes

Dexter explains that from the beginning of Dexter Morgan and Sergeant James Doakes working together, the latter always had an overt suspicion of the former – mostly just thinking he was weird for being so into blood. Once Dexter’s underwater graveyard of victims is discovered in season 2, the entire police department must search for the Bay Harbor Butcher without realizing he’s working alongside them. While many in the department shoot down such suspicions, Doakes stalks Dexter as he truly believes him to be the killer. After hunting Dexter to one of his kills, he becomes Dexter’s hostage in a remote cabin. After a few episodes of Dexter keeping Doakes in a cage and revealing his serial killing, Dexter’s girlfriend Lila shows up to kill Doakes herself. Since Doakes had the killing weapons and Dexter’s blood slide box, the department wrongly pinned him as the Bay Harbor Butcher.

Lila West

Lila is introduced in season 2 as Dexter’s sponsor at Narcotics Anonymous, who invents the phrase “dark passenger” for him and the two engage in an affair. Dexter never actually tells Lila about his serial killing, she finds out when she tracks Dexter’s GPS and finds Doakes. Doakes then informs Lila that Dexter is the Bay Harbor Butcher, so she decides to protect him by setting the cabin afire with Doakes inside. Dexter later tracks down Lila to Paris and kills her by stabbing her in the heart.

Miguel Prado

Portrayed by Star Wars prequels actor Jimmy Smits, Miguel Prado is introduced in Dexter season 3 as the D.A. looking for whoever killed his young brother, who just happens to be Dexter Morgan. While trying to hide his own identity and accidental kill, Dexter goes to kill Freebo, suspected of killing Miguel’s brother, where Miguel catches him with the murder weapon in his hands. Miguel believes that Dexter killed Freebo in self-defense, whereafter they become best friends, spending much time together outside of the investigation. As they grow closer, Miguel finds out Dexter has avenged other deaths, eventually revealing to Miguel that he is a serial killer. Miguel becomes Dexter’s sidekick where they find victims together, though Miguel killing Ellen Wolf undeservedly and attempting to kill LaGuerta lead him to become Dexter’s next victim.

Lumen Pierce

Introduced in Dexter season 5, Lumen Pierce was found by Dexter as a hostage in the home of one of his murderous victims. When Dexter saw Lumen, she knew that he had just killed Boyd Fowler. Dexter and Lumen then team up where they hunt down her other torturers in the Barrel Girl Gang, whereafter they begin a romantic relationship. Lumen is the first person to which Dexter can truly disclose his life’s story, telling her that he has killed habitually and it’s who he is. She stays with him throughout the rest of the season until they have killed every member of the Barrel Girl Gang, after which Lumen departs Miami and stops killing.

Maria LaGuerta

Although for most of the series Maria LaGuerta was adamantly against putting Dexter under suspicion of killing, she concludes that he is the Bay Harbor Butcher herself in Dexter season 7 shortly after Debra also learns the truth in season 6. She ardently believes James Doakes wasn’t the killer, discovering the evidence could also lead to Dexter. LaGuerta then stalks Dexter and tries to set him up by catching him at kills, finally finding him in the middle of killing Hector Estrada at the shipping yard. She confronts Dexter before Deb shows up, where Deb has to choose between protecting her brother or killing her innocent boss. Deb hesitantly decides on the latter, leaving Dexter’s identity secret.

Hannah McKay

Hannah McKay was introduced in Dexter season 7 as the accomplice to a serial killer when she was younger. Dexter then discovers that Hannah has still been killing, deciding to put her on his table. The moment Hannah discovers Dexter’s dark passenger is when she wakes up on his table, though instead of killing her they end up becoming intimate. Dexter tells her he kills “bad people,” which is a description they both agree she fits. Dexter refuses to kill Hannah, even when Deb asks him to, because they are in a romantic relationship. Over the next two seasons, Hannah remains Dexter’s on-and-off girlfriend until he abandons her with his son Harrison Morgan in Dexter‘s season 8 finale.

Isaak Sirko

For much of Dexter season 7, the antagonists are a group of Ukrainian mobsters in the Koshka Brotherhood who track down Dexter after he killed one of their own. Isaak learns that Dexter killing Vikor wasn’t out of vengeance, he’s just an animalistic killer. Dexter and Isaak come to an understanding where they agree to kill Isaak’s mafia acquaintances, though Isaak is fatally wounded by George before Dexter can get to him.

Dr. Evelyn Vogel

In season 8 of Dexter, a new psychologist, Dr. Evelyn Vogel, comes to Miami to help on The Brain Surgeon case. She reveals to Dexter that she knows him even if he doesn’t know her because Harry had come to see her in therapy once discovering Dexter had psychopathic tendencies as a child. Dr. Vogel tells Dexter that she was the one who helped Harry design the “Code of Harry” that Dexter lived by, where she had originally suggested using Dexter’s blood affinity for good. She calls herself Dexter’s “spiritual mother” as she helped turn him into the moral serial killer he became.

Zach Hamilton

Zach was another young psychopathic patient of Ellen Vogel, to whom Dexter was assigned to teach the Code of Harry for killing. Although he showed promise in following Harry’s Code for killing, Zach was murdered by The Brain Surgeon toward the end of Dexter season 8.

About The Author

Jordan Williams
(812 Articles Published)

Jordan Williams is a Movie/TV Feature Senior Staff Writer for Screen Rant. She graduated from the University of Oregon in 2020 with a B.A. in Psychology and a minor in Media Studies.

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Jordan is based in Seattle, Washington and enjoys exploring the natural beauty the PNW has to offer. She runs on coffee and classic movies, taking pride in having watched every film on AFI’s 100 Greatest Films list and every Best Picture Oscar winner.

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