|First appearance||"The Detail" (episode 1.02)|
|Last appearance||"–30–" (episode 5.10)|
|Created by||David Simon|
|Portrayed by||Corey Parker Robinson|
|Occupation||Detective in the Baltimore police department's major crimes unit|
Leander Sydnor is a fictional character on the HBO drama The Wire, played by actor Corey Parker Robinson. Sydnor is a young, married Baltimore Police detective who was a member of the Barksdale detail and later worked in the Major Crimes Unit.
Season 1 
Sydnor was assigned to the Barksdale detail from the Auto Theft Department after Lieutenant Daniels requested Sydnor's commanding officer, Lt. Cantrell, give him his best detective to balance out having to take "his worst" – the erratic Detective Pryzbylewski. Once in the detail, he was partnered with Detective Lester Freamon and the pair looked into the Barksdale organization's paper trail. Sydnor also performed valuable undercover work, making hand-to-hand buys to build evidence, alongside Detective Kima Greggs and her informant Bubbles. Bubbles helped Sydnor with the credibility of his undercover "junkie" image, recommending subtle but important changes such as not wearing his wedding band ("you're married to the needle now") and walking on empty drug vials so that the shards stuck in the soles of his shoes. Sydnor was also responsible for identifying Avon Barksdale at the annual West-Side versus East-Side basketball game. He later told Freamon, who had become something of a mentor to the young detective, that the Barksdale investigation was the best police work he had ever done.
Season 3 
Sydnor returned to working in his old district after the dissolution of the Barksdale detail. When Daniels established a permanent Major Case Unit he was allowed to choose his own detectives and encouraged Sydnor to transfer in. Sydnor took up the offer and again worked on investigating the Barksdale organization.
Season 4 
In Season 4, the Major Case Unit was investigating Marlo Stanfield in addition to the Barksdale money trail. With Cedric Daniels promoted to Major, Lester Freamon was the de facto commander of the unit, having been allowed to hand-pick their shift lieutenant Jimmy Asher, a soon-to-retire officer who took an entirely hands-off approach to the unit's investigations. When the money trail led investigation to major political figures, Sydnor worried about the potential damage to his career; nonetheless, he personally delivered a subpoena for financial records to State Senator Clayton "Clay" Davis.
Senator Davis angrily protested the subpoenas to Mayor Clarence Royce, who then ordered Commissioner Burrell to rein in the Major Crimes Unit. Deputy Commissioner William Rawls suggested that proper supervision was all the unit needed and replaced Lieutenant Asher with Lieutenant Marimow. Marimow is a caustic commander with a reputation for being a "unit killer". Marimow's command style drove away Freamon and Greggs leaving only Sydnor and Massey. Sydnor decided to leave the unit at the first available opening. With the transfer of Sergeant Thomas "Herc" Hauk and Officer Kenneth Dozerman into the unit Sydnor found two allies in his desire to make cases (and who shared his dislike of Marimow), but ultimately the unit was unsuccessful at building a case against Stanfield under Marimow's supervision. Over the course of the season, Sydnor mentored Dozerman, and also cautioned Herc on the consequences of lying to Marimow but Herc nevertheless continued to act in an unprofessional and often counterproductive manner while in the unit.
The unit was eventually reconstituted under the control of Freamon after Daniels was promoted to CID colonel. Under Freamon's leadership, Asher was named Lieutenant again, and Jimmy McNulty and Kima Greggs transferred back into the unit. Dozerman remained with the unit while Herc was suspended pending an internal investigations division investigation. As the season ended, a new investigative strategy was mapped out against Marlo Stanfield.
Season 5 
After more than a year of investigation into the Stanfield Organization the unit still did not have a strong enough case to file charges. When budget cuts in the department eventually led to the unit being closed down, Sydnor was disappointed to find his work wasted and realized that simply keeping Stanfield under surveillance was effective in reducing crime. Sydnor and Lester Freamon were detailed to the State's Attorney's office to prepare the corruption case against Clay Davis. Sydnor and Freamon first prepared the paperwork on Davis and then assisted Rhonda Pearlman in a series of Grand Jury depositions.
Sydnor uncovers evidence of Davis having committed a federal crime when he finds that Davis borrowed money from his mother for a mortgage deposit. Freamon realizes the significance of the crime and knows that it could mean a thirty-year jail term. The detectives present the evidence to State's Attorney Rupert Bond and he refuses to take the case federal as he wants to prosecute Davis himself for political reasons. In the series finale, Sydnor visits Judge Daniel Phelan in his chambers to apply back-channel pressure in order to advance an investigation, much like McNulty did in Season 1.
- "Org Chart - The Law". HBO. 2004. Retrieved 2006-07-22.
- "Character profile - Detective Leander Sydnor". HBO. 2004. Retrieved 2006-07-22.
- Joe Chappelle (2008-01-06). "More with Less". The Wire. Season 5. Episode 1. HBO.
- "The Wire episode guide - episode 51 More with Less". HBO. 2008. Retrieved 2008-01-22.
- Ernest Dickerson (2008-01-13). "Unconfirmed Reports". The Wire. Season 5. Episode 2. HBO.
- "The Wire episode guide - episode 52 Uncomfirmed Reports". HBO. 2008. Retrieved 2008-01-22.
- Scott and Joy Kecken (2008-01-20). "Not for Attribution". The Wire. Season 5. Episode 3. HBO.
- "The Wire episode guide - episode 53 Not for Attribution". HBO. 2008. Retrieved 2008-01-22.
- Dan Attias (2008-01-27). "Transitions". The Wire. Season 5. Episode 4. HBO.