S6:E10 We're winding down towards the end of the season and now that it's been announced the show has been renewed for two more seasons (and then it will probably end), we're constantly on the lookout for signs if Dexter will ever be caught. And I believe he will be, based on the facts that Deb is debating whether or not he is worthy of her suspicion, he seems to be getting careless (Deb found a pen in his bag that proved he went to Nebraska), and he's becoming more and more obsessed with his kills. Additionally, Dexter seems to despise Harry more and more (which is the reason he's remained out of prison for this long), and we witnessed several incidents this episode where Dexter openly rejected Harry.
"No, Professor Gellar, I did not kill you." - Travis
After Dexter finds Professor Gellar’s body in the freezer, he looks through a window and sees Travis having a conversation with himself. Dexter listens, and hears Travis telling Gellar he didn’t kill him. We then see Gellar, and watch him as he tells Travis “yes, you did kill me, because I told you how delusional you were.” Then we learn three years ago, Travis approached Gellar with some ideas about the Book of Revelations and asked him to steal an ancient weapon from the University. But Gellar said he wasn’t going to help him do anything illegal, and that’s why Travis killed him and became a serial killer. After Travis leaves the church, Dexter stays and as he’s looking around, he gets a text from Deborah saying they are tracking the IP address of Gellar’s blog, which meant police would be at the church soon. Dexter decides to keep Gellar’s body hidden from the police for the time being, because it might help lead him to Travis. He quickly amputates one of Gellar’s hands and puts his fingerprints on an axe so the police will keep looking for him, which means Dexter will be the only one hunting Travis. Harry tells him to back off and to let the police handle Travis, but Dexter says he can't because the only way to stop him is to kill him. Dexter and Harry's conversation continues, and Dexter directs some surprisingly harsh statements to his dead father, which is noteworthy because it's the first time he's ever seemed to abhor his presence. Later in the day, Dexter is called back to the church and as his colleagues are searching around, he checks Gellar’s blog (which again, is really written by Travis) and sees a new post about how the “false prophet will be punished” and that Travis “made a mistake listening to the false prophet.” Dexter assumes Travis is referring to him as the false prophet, and figures out the mistake Travis wants to fix is Holly Madison, the woman he captured and planned to sacrifice but then let go because Dexter talked to him about not having to succumb to the urges. It seems to me that these episodes are slowly showing us how Dexter will eventually be caught. Deb is suspicious about what he does in his private life, he's acting impulsively, yelling at Harry, and generally not being as cautious as he usually is. But by far the most significant part of this episode was how Dexter is slowly starting to reject Harry, and his recommendations. In previous seasons, Harry has guided Dexter and kept him safe from capture -- but now, Dexter is acting on his own impulses instead of following Harry's advice...which means when he stops listening to Harry completely is when he'll be caught by authorities.