1. We learn early on — via old videotaped sessions between Dexter’s dad, Harry, and Dr. Vogel — that Dr. Vogel came up with Harry’s Code as a way to channel Dexter’s psychopathy. “I developed a framework for your survival. That’s what mothers do.” IS DR. VOGEL DEXTER’S REAL MOM? No. She’s not. We already know that Laura Moser is his real mom.
Anyway, Dr. Vogel was an expert witness on a few of his homicide cases and became friends with Harry. He went to Vogel because he had no one else to talk to about Dexter. We’ll probably find out later that Harry and Dr. Vogel were “more than friends.” After all, young Dr. Vogel looked like this (humana humana humana).
2. Interestingly, now we know the origins of the blood slide trophies, too. Young Harry reveals that Dexter stole a blood slide from one of Harry’s crime scenes. He’s also always forced his victims to look at pictures of their own victims before he kills them because Dexter has an “innate sense of justice.” She thinks he’s “making the world a better place.” Vogel also believes that psychopathy is not necessarily a bad thing.
3. The new murder victim is missing a brain piece, confirming Vogels’ theory that he’s a serial killer and, because he’s sending her the brain pieces, allegedly also a former patient. Dr. Vogel is kind of blackmailing Dexter to find and kill the brain surgeon serial killer. She doesn’t want the authorities to get involved because they might find out about her “unorthodox” (i.e. illegal) methods.
4. Initially, it appears that the killer’s name is Lyle Sussman, who is actually not a former patient of Dr. Vogel’s. He’s a nobody, which is why we know that he’s not the actual brain surgeon killer. When Dexter tracks Sussman down, he finds him hanged. Who killed him? Turns out, Sussman was coerced into killing his victim.
5. Side note: Does Dexter ever use his blood spatter skills arrest ANYONE, or does he kill all of his subjects? His arrest record must be terrible, and Miami must have the highest rate of unsolved murders in the country.