11. Stan Liddy and Joey Quinn - Season 5
Stan Liddy was a corrupt police officer in the narcotics division, before being fired after a failed sting operation. He's then hired by Joey Quinn to investigate Dexter, because Quinn believes Dexter may be involved in Rita's death. Though an interesting part of season 5, the Liddy/Quinn investigation felt a lot like 'Doakes 2.0,' and the fact that Quinn has never decided to follow-up on his original suspicions of Dexter is just ridiculous. Especially in season 7, when LaGuerta arrests Dexter for being the Bay Harbor Butcher (but more on that later).
Memorable Moment: Liddy, to Quinn: "Dexter... the f**k kind of name is Dexter?"