Stan Liddy was a character in DEXTER. He is initially introduced as a corrupt police officer in the Narcotics division being arrested after a sting operation. After his suspension (and eventual termination), Liddy focuses on uncovering Dexter's secret, which he is originally hired to investigate by Joey Quinn.
Liddy is portrayed as a man in his late 50s. He has thinning grey hair, piercing eyes and a low, distinctive voice tinged with a Southern American accent. He is frequently seen wearing flamboyant Hawaiian shirts.
Stan Liddy is a highly eccentric character. He holds an easy-going attitude around those he likes, but quickly reverts to a tough-cop persona when needed. In reality, Liddy is selfish, arrogant, miserly and manipulative, and at times can even be considered cold-blooded and threatening.
Liddy develops an obsession with uncovering Dexter's secret, so much so that he illicitly enters the Miami Metro Police building, signs out various pieces of surveillance equipment and then sets them up in Dexter's apartment in an illegal attempt to gain access to Dexter's secret.
In order to clear Sgt. Angel Batista of a serious violation within Internal Affairs (he basically beat down a Sergeant in the Sheriff's department) involving Sgt. Lopez, Lt. Maria LaGuerta agreed to assist Jim McCourt in a sting operation to bust a dirty narcotics cop known as Stan Liddy. Unfortunately for the operation, Angel Batista assumed due to LaGuerta's recent evasive attitude and late-nights out as a sign of an affair with Jim McCourt, causing him to follow them to the motel where the sting was taking place and bust in on the operation, thus ruining the entire operation. After a brief fight between the married couple, everyone departs with Liddy sitting in the background watching everyone before he's asked to stand up and leave with an officer.
Apparently Stan was released either due to a lack of evidence or otherwise as he is later seen in a bar sitting next to Detective Joey Quinn. The two begin talking trash to one another, but in a friendly manner that wouldn't really lead to a fight. Quinn then brings up the fact that he needs to look into a guy and Liddy looks at him with a serious, stern look upon his face saying (and I quote) "If you fuck with the bull, you get the horn". The two stare off, with Quinn understanding what he's getting into and then they both begin to laugh...with Liddy asking the guy's name that he needs to look into. Quinn tells him that it is Dexter Morgan, whom he has been suspicious of since mostly last season and especially after his wife, Rita Bennett's, death. Liddy remarks that Dexter is a weird kind of name.
As Quinn and Debra's relationship grows, Liddy becomes annoyed at Quinn for being in a relationship with their suspect's sister. Checking Dexter's background, Liddy becomes convinced that Dexter is dirty, because the file is simply too clean. Suspecting drugs or worse, Liddy becomes even more interested in the case than Quinn, whose feelings for Debra are causing him to have second thoughts. As Liddy learns about Lumen residing in Dexter's old house, Liddy begins to demand more cash from Quinn. After Quinn relents and gives up more cash, Liddy fakes a car accident as a means to gain Lumen's identity (noting the stupidity of Lumen's name as well). Showing up at Quinn's house, something Quinn forbid so Liddy could avoid Debra. Threatening to tell Deb what Quinn has been up to, Liddy extorts even more cash from Quinn. As Dexter and Lumen dump the remains’ of Cole, Liddy is revealed to have followed them. Using a telescopic lens, he takes several pictures of them dumping the body. He takes these photos to Quinn, speculating the bags contain drugs at best or a body at worse, which Quinn finds hard to believe. Giving him the last of his cash, Quinn tells him to back off, due to falling in love with Debra and aware hiring Liddy was a betrayal to her. Liddy, however, refuses, believing what he stumbled on could revive his career and embarrass Homicide. Taking the photos, Liddy offers to show Debra what her brother was up to. Enraged, Quinn pins Liddy to the door and tells him never to come near Debra or himself. Unafraid, Liddy laughs at Quinn’s attempt to scare him and walks away.
Liddy continues keeping his eye on Dexter and Lumen throughout the course of the next few episodes, even encountering Dexter just before he purchases equipment to watch them in their house. Dexter eventually catches onto the fact that they were being watched (via his babymonitor picking up the signal) and he traces the equipment back to Quinn, whom he assumes was after him. During this time, it is revealed that Liddy was finally canned by the police department and intends to use a bust on Dexter to get him back in the force, but he needs Quinn's help. Quinn, however, is still out of the situation, which didn't phase Liddy in the slightest.
Dexter juggles his ordeals with Jordan and Quinn, choosing to deal with Quinn first. After seeing who he thinks is Quinn enter a surveillance, Dexter readies an inject of M99 and approaches the van. However, Liddy is waiting and tases Dexter and throws him into the van, driving off to a secluded location where he intended to have Quinn make the bust for him. After overhearing a phone conversation, Dexter learns that Quinn no longer supports Liddy's investigation and Liddy is the only one who wants to make a profit from it. Liddy shows Dexter digital footage he captures using hidden cameras on his laptop, but admits that he did not have the legal right to obtain any of it, so none of it could be used in court. However, he offers Dexter a deal: if Dexter gives him a full confession, Liddy promises to leave Lumen out of everything.
After procuring a video camera, Liddy stands up begins to videotape Dexter again, when he is suddenly kicked in the face and sent flying towards the front seat of the van. Despite having his hands and feet bound, Dexter manages to struggle with Liddy, who pulls a knife to tries and kill Dexter with it. Dexter, however, is able to turn the blade enough to force it slowly into Liddy's chest while responding in self-defense. Liddy resists at first, but as the knife sinks in deeper his eyes widen and he is unable to struggle any longer. He dies quickly.
Quinn arrives on scene just as Liddy takes his last breath and checks the van (which is locked in the front, then on the sidedoors by Dexter himself). Quinn even tries calling Liddy's phone but Dexter cancels out the call so that he can't be found out. Quinn gets frustrated and gives up, but before he walks away a drop of Liddy's blood leaks out of the van and lands on his shoe, though Quinn fails to notice. After Quinn drives away, Dexter emerges from the van. Though he says he does not have time to deal with Liddy's body, he does take the time to remove the tape from Liddy's camera and destroy his laptop by tossing it into the ocean.
The police find Liddy's body, and Quinn is considered a suspect, due to Liddy frequently calling him and the blood on his shoe. Quinn refuses to say what the nature of their relationship was, likely to protect Debra. Realizing how much Quinn means to Debra, Dexter sabotages the blood test, making it appear that it was not Liddy's blood on Quinn's shoe, clearing him. Quinn later thanks Dexter for this, although Dexter pretends to not know what Quinn is talking about.
- He is played by Peter Weller, the lead character of the cult-hit film RoboCop. Because of his involvement this season, along with other high profile actors such as Julia Stiles and Jonny Lee Miller, as well as John Lithgow last season, DEXTER is shaping up to carry a lot of big stars.
- Outside of the Robocop film franchise, Weller is credited for playing corrupt characters in films such as A Killing Affair, Shoot the Moon and Firstborn. These film credits could be why Weller was cast as the corrupt cop Liddy.
- The character of Liddy may be based partially on Detective Coulter in Dexter novels, who first appeared in Dexter by Design. Both are eccentric, seemingly dim-witted police officers who prove to be very intelligent, both discover Dexter is a murderer and both attempt to use it to further their own careers.
- He is the one of two main antagonists who doesn't kill someone while appearing in the series, the other being Jacob Elway.