<P> "Born Free" was written by Daniel Cerone and executive producer Melissa Rosenberg, and was directed by Michael Cuesta . Cerone and Rosenberg have written two previous episodes each, while this episode marked Cuesta's fifth time returning as director . Guest stars in this episode include Geoff Pierson, C.S. Lee, Mark Pellegrino, Christian Camargo, Judith Scott and Scott Atkinson . Rudy's apartment was set in Miami, Florida, however filming took place in Long Beach, California . The apartment was a brown, triangular apartment condo, so the producers altered its appearance; a false brick wall was placed in front of the garage entrance and a door was created . The producers also concealed a narrow door of the garage entrance with a potted plant, and added false window panes to the windows, concealing the existing vertical blinds . The shipping yard shown in the episode was set in the Port of Miami, yet filming took place in a port dock at the Port of Los Angeles . The scene was filmed in San Pedro, California, in a waterfront lot of Harbor Boulevard . </P> <P> The first season of Dexter is based on the novel Darkly Dreaming Dexter by Jeff Lindsay . However, there are numerous differences, ranging from extra subplots to rearrangements and modifications of elements from the source material . The biggest change is the lead - up to and revelation of the identity of the "Ice Truck Killer", called the "Tamiami Butcher" in the novel . In the novel, Dexter is led to believe that he might be the one committing the murders, due to a series of strange dreams that connect him to the murder . The final clue is a blurry photo, taken from surveillance footage, of a man who resembles Dexter at a crime scene . After the "Tamiami Killer" kidnaps Deborah, Dexter finds and confronts him . It is subsequently revealed that the killer is actually Dexter's nearly identical long - lost brother, Brian, who, like Dexter, witnessed their mother's brutal murder . Dexter is followed by Detective LaGuerta, who is slain by Brian . Debra finds out her brother is a killer and Dexter helps Brian to escape . In the television series, Brian is introduced under the fake name Rudy, a prosthetist who becomes Debra's boyfriend . Dexter hesitantly kills Brian instead of letting him escape, Debra does not discover her brother's secret, and LaGuerta is not present at all in the confrontation . In the novel, Dexter and his brother are nearly identical, whereas the actors playing the two characters are distinct from each other in their looks . </P> <P> "Born Free" was the most - watched original series telecast on Showtime since 2004, when the Nielsen ratings started separating the channel's ratings from Showtime Plex, the package of Showtime channels offered by most cable and satellite systems . The finale drew an audience of 1.1 million American viewers, a significant increase over the series premiere, which attracted slightly more than 600,000 viewers . The first season attracted on average 1.96 million American viewers, including live and DVR viewing off the premium channel's main feed . "Born Free" brought in 589,000 viewers on its first free - to - air broadcast in Australia . Hall submitted the episode for consideration for a Primetime Emmy Award for Outstanding Lead Actor in a Drama Series, but was not ultimately nominated . </P> <P> Eric Goldman of IGN said that "Born Free" was "an intense episode that brought the Ice Truck Killer story to a satisfying conclusion ." He felt that the "biggest shock of all" was the reveal of Rudy as Dexter's brother, and described their confrontation as "riveting". Goldman gave the episode an "incredible" rating of 9.5 out of 10 . Paula Paige of TV Guide was "impressed" by Michael Hall's "incredible acting ability," praising his ability to transform from a "stoic killer to overwrought brother in a matter of moments ." She said that the series went "from being a good show to a fantastic show in the course of one season," and hoped that "the sophomore season will be just as terrific ." Jonathan Toomey of TV Squad felt that it would be a "shame" if Hall did not win a Golden Globe Award, saying that he "certainly deserves it ." He understood why Rudy wanted to make Debra the brothers' first victim together; Rudy was jealous of the life that Dexter received and killing Debra was the symbol of that life dying . Although Toomey said that the episode was "really well written," he was troubled that no one made the connection between Dexter and Rudy when all they had to do was read Rudy's file, but Toomey speculated that it could be discovered the next season . </P>

When does deb find out rudy is dexter's brother