History Characters / CSI

->Played yy:Bahar Soomekh

%%* OneSceneWonder: Since she's the Day Shift Coroner, she usually isn't involved in the cases of the Night Shift. Her one appearance in "Genetic Disorder" came about because the VictimOfTheWeek was found in Doc Robbins' house and neither he nor David Phillips could autopsy said victim without inviting suspicions about inconvenient facts being covered up.

* FairCop

[[folder:Dr. Dr. Milton Hudson]]

* TheRookie: The newest CSI on the team and still very much learning on the job.

->Played by: Creator/JayLee
* BadInfluencer: Albeit unintentionally. His pre-CSI crime solving TikTok videos get a seeminly innocent person released, only for it to turn out years later he was wrong and he helped release a murderer.
The
[[/folder]]

The

* BigSisterInstinct: While they aren't related, she seems to feel this way towards Greg (who's about 20 years younger). For one, she seems the most upset when he is nearly beaten to death in "Fannysmackin."

* ArchEnemy: [[Natalie Davis]] quickly becomes this to Gil Grissom, [[spoiler:especially after she kidnaps Sara and leaves her for dead.]]

* SiblingMurder: [[spoiler: As a child, she murdered her sister Chloe by pushing her out of a treehouse, because she was jealous of the attention her sister was receiving after her mother's death. This is also what causes her thing regarding bleach, as her father used it to clean her sister's blood off of the concrete.]]
* TheHeavy: Has this on Grissom long after [[spoiler:she's]] in prison, only matched by Millander and later Nate Haskell for Ray Langston.
* ThatOneCase: One of the most unique villains in the history of the ''C.S.I.'' franchise, [[spoiler:her]] entire M.O. with creating miniatures of future murder scenes then executing the scene to exacting standards became a hot topic both in the show and in real life for the 2006-2007 TV season.
* TheUnfavorite: [[spoiler: She was this as a kid, and it's implied her first kill was her older sister, in an attempt to finally get attention]].

** TheBusCameBack: He does have a cameo in season 12's "The Two Mrs.Grissoms," and returns at last for the series finale, which originally aired in September 2015.

[[folder:The Miniature Killer/ [[spoiler:Natalie Davis]]]]

* ArchEnemy: Quickly becomes this to Gil Grissom, [[spoiler:especially after she kidnaps Sara and leaves her for dead.]]

* TheBusCameBack: [[spoiler:Davis returns in one of Peterson's last episodes for a hearing about whether or not to transfer her to prison, which they do. She has worked over her bleach problem by this time.]]

** In-universe, he cites three Berserk buttons:

* WhipItGood: Used horrifyingly in "Pirates of the Third Reich" when [[spoiler:she captures Sneller, ties him to her car, and proceeds to try to whip him ''to death''. Grissom talks her out of it]].

* NonIndicativeName: He is named after [[TheStrangeCaseOfDrJekyllAndMrHyde Dr. Henry Jekyll]] even though the killer does not have an [[JekyllAndHyde evil split personality]] and Jekyll is supposed to be the good one. Furthermore, while most versions of Jekyll are medicinal doctors, none of them are surgeons who performed gruesome operations on innocent people.

[[folder:Maxine "Max" Roby]]
->Played by: Creator/PaulaNewsome

[[/folder]]

[[folder:Maxine "Max" Roby]]
->Played by: Creator/PaulaNewsome

[[folder:Joshua Folsom]]
->Played by: Creator/MattLauria

[[folder:Ahalaya "Allie" Rajan]]
->Played by: Creator/MandeepDhillon

[[folder:Christopher "Chris" Park]]
->Played by: Creator/JayLee

[[folder:Beau Finado]]
->Played by: Creator/LexMedlin

!! Lab Technicians

[[folder:David Hodges]]
[[quoteright:183:https://static.tvtropes.org/pmwiki/pub/images/David_Hodges_1526.jpg]]
->Played by: Creator/WallaceLangham

* BornLucky: But only on a single day: April 7th. It's his lucky day. On this day, ''nothing'' has ever gone wrong for him, ever. In "Lab Rats," he takes advantage of it being his lucky day to help crack a case that even Grissom couldn't figure out.
* BrilliantButLazy: Unlike most Lab Rat characters on the CSI shows, Hodges is quite content to remain indoors and hates going into the field.
%%* BunnyEarsLawyer
%%* DeadpanSnarker
* DirtyCop: Averted. [[spoiler:The first episode of the revival uncovers evidence that, during his time at the lab, he faked results by the truckload, putting any conviction resulting from said fake lab results in jeopardy. Sara believes it to be a FrameUp, but the DA wants Hodges arrested anyway, and every one of the cases he was involved in is now under scrutiny. Sara, Gil, and the new CSI team manage to fully clear his name by the finale, thus saving the crime lab's integrity as well.]]
* HiddenDepths: Among other things he's a big sci-fi geek, with an undying love for "Astro Quest" (fictional couterpart of ''Series/StarTrekTheOriginalSeries'').
* LargeHam: Has his moments, but the "Astro Quest" episode (and the dream sequences that have Hodges as TheCaptain of the ShowWithinAShow) are pretty much a chance for Langham to unleash his inner Creator/WilliamShatner in a homage to "''The Gamesters Of Triskelion."''
* MommasBoy: He is living with his mother when he first starts working at the lab. When she finally appears on-screen, we learn that she's a surprisingly attractive and classy lady, and far from the typical MyBelovedSmother that most mothers involved in this trope are.
* TheNoseKnows: Has an incredibly accurate sense of smell. In "In Vino Veritas," he leans into a wine barrel that had held a corpse for a few days and deeply inhales, grossing out a co-worker. He explains that he can determine the source of the wine from the various ingredients he detects...over the smell of decomp. In "The Theory of Everything", Catherine has him get down on the floor of a victim's bedroom and smell the carpet for evidence, as he possesses the genetic makeup that lets him smell the presence of cyanide.
* PetTheDog[=/=]EstablishingCharacterMoment: For the first couple of his seasons, he is portrayed as a through-and-through {{Jerkass}} ProfessionalButtKisser with no redeeming qualities whom all his co-workers hate. In Season 7, however, he gets a surprising amount of CharacterDevelopment in a scene where he has to break bad news to a victim's family, and he's portrayed as a sympathetic character ever since and even joins the main cast. He even gets a wife and by the end of season 1 of the revival, a child.
%% * PromotionToOpeningTitles
%% * TheReliableOne
* SmallNameBigEgo: He acts like he's much more important than everyone else. Can occasionally cross into InsufferableGenius.
* WhyDidItHaveToBeSnakes: He has an inordinate fear of birds.

[[folder:Wendy Simms]]
[[quoteright:175:https://static.tvtropes.org/pmwiki/pub/images/csiwendysimms.jpg]]
->Played by: Creator/LizVassey
%%* TheLabRat: Although she wants to become a "field mouse."
* MsFanservice: Particularly in Hodges' fantasies of her. In one she's only wearing a ''bikini''.
%%* PromotionToOpeningTitles
* PutOnABus: In universe: Left for Portland's lab.

[[folder:Mandy Webster]]
->Played by: Creator/SheeriRappaport
%%* DeadpanSnarker
* ReallyGetsAround: Some of her comments in the lab rats' DayInTheLimelight episodes hint at this.
%%* TheLabRat

[[folder:Archie Johnson]]
->Played by: Creator/ArchieKao
* AsianAndNerdy: He's a computer analyst and a Franchise/StarTrek geek. Could be {{subverted}} since he does have 'cool' hobbies like surfing and snowboarding.
%%* TheLabRat

[[folder:Henry Andrews]]
[[quoteright:175:https://static.tvtropes.org/pmwiki/pub/images/csihenryandrews.jpg]]
->Played by: Creator/JonWellner
* ButtMonkey: "Appendicitement" and "Field Mice" are the biggest examples.
%%* CannotTellAJoke
%%* TheLabRat
%%* PromotionToOpeningTitles: Wellner gets this beginning in Season 13.

[[folder:Bobby Dawson]]
->Played by: Creator/GeraldMcCullouch
%%* ButtMonkey: In Hodges' "Lab Rats" board game.
%%* GunNut
%%* TheLabRat

[[folder:Ronnie Litra]]
->Played by: Creator/EricStonestreet
%%* BigFun
* ChuckCunninghamSyndrome: Just vanishes after Season 4 or so.
%%* TheLabRat

!! Police

[[folder:Captain James "Jim" Brass]]
[[quoteright:230:https://static.tvtropes.org/pmwiki/pub/images/Brass-CSI-Guilfoyle-230x300_5789.jpg]]
->Played by: Creator/PaulGuilfoyle

* AllOfTheOtherReindeer: "A Bullet Runs Through It," where the other cops shun him at the dead officer's funeral.
* BerserkButton: Bad fathers, likely because he wishes ''he'' [[MyGreatestFailure could've been a better one]].
* BlindPeopleWearSunglasses: In the revival, he’s wearing them before revealing his eyes which were damaged in an attack. He’s not completely blind but can’t see very well.
%%* CoolOldGuy
* DeadpanSnarker: On Vegas' staggeringly-high murder rate: "We're very competitive!"
* DirtyCop : Originally a big subversion of this, stating how he refuses to be bought or get dirty, but drifts into that territory as of the end of season 11. [[spoiler:He covers for Ray when Ray kills Nate Haskell, and is reluctant to help catch a killer who was killing other killers.]]
* EtTuBrute: In "A Bullet Runs Through It," he feels this way when one by one, all of the other officers walk away from him at the dead officer's funeral.
* HandicappedBadass: He's in his 70s and half-blind come the revival series, but it opens with him kicking and killing the ass of a man sent to kill him.
* HiddenDisdainReveal: Despite trying to help his daughter, even knowing she isn't actually his, every time she gets herself into trouble. [[spoiler:After a crime of hers gets her mother killed, he flatly tells her that she killed the only person who cared about her.]]
%%zce* JerkWithAHeartOfGold: Eventually mellows out into this.
* MrExposition: He's the man who gives both the team and the audience information on the latest victim of the week.
* OutrankingYourJob: Spends a lot of time personally investigating crime scenes and chasing down suspects for a police captain.
* ParentalIssues: He still loves his daughter despite knowing that she's not genetically his. Her...not so much, to the point that when Brass is shot he gives power of attorney to Grissom rather than to her. Another contributing factor is probably that she has been addicted to drugs and worked as a prostitute for a time, so it would be understandable for Brass to doubt her judgment in general.
* PutOnABus: Takes a leave of absence for season 15 [[spoiler: after his daughter fakes her kidnapping with the help of a boyfriend, gets Brody involved and almost kills her, kills the boyfriend, and kills her mother (whom she didn't expect to come to Las Vegas) because she would have recognized the boyfriend. Amazingly Brass is helping her with her trial.]]
** TheBusCameBack: Comes back for the finale, and for a few appearances in the revival.
* SemperFi: Vietnam Marine vet.

[[folder:Sofia Curtis]]
[[quoteright:215:https://static.tvtropes.org/pmwiki/pub/images/sofia-curtis5903757600ml_4738.jpg]]
->Played by: Creator/LouiseLombard

* ActionGirl: Oh yeah. And given her profession, it's absolutely necessary for her survival.
* ChuckCunninghamSyndrome[=/=]PutOnABus: Is a semi regular for three seasons, a regular character in one season, and then vanishes without a trace, or explanation.
** TheBusCameBack: Returns late in Season 11. [[RankUp She's Deputy Chief now.]]
%%* FairCop
* HeroicBSOD: In "A Bullet Runs Through It," when she believes she shot a fellow cop.
%%* MrExposition: Basically, a female Jim Brass.
* RankUp: She starts out as his subordinate but ends up being Captian Brass' boss.

[[folder:Conrad Ecklie]]
[[quoteright:256:https://static.tvtropes.org/pmwiki/pub/images/ecklie-imgres-78_6171.jpeg]]
->Played by: Creator/MarcVann

* ADayInTheLimelight: The B-plot of one episode features Ecklie handling the investigation himself when the main characters are unavailable.
* AmbitionIsEvil: The real reason he is such an ass to Grissom and the team was because he thinks that Grissom has the same ambitions he does. Once he realizes that Grissom and the team won't keep him from fulfilling his goals, he eases off considerably.
** His behavior in the Season 14 episode "Consumed," though, suggests that running for sheriff may cause him to relapse.
* BigBad: Arguably, of Season 5. He never does anything illegal, but his antagonistic actions drive the overarching plot of that season.
* CharacterDevelopment: A fairly significant example of this. He's almost a completely different person now than he was in season 1. He makes a pretty seamless transition from {{Jerkass}} to JerkWithAHeartOfGold. After 13 seasons he's still a bit nasty at times, but he has the respect of the team and the department as a whole, and he has absolutely become a ReasonableAuthorityFigure. (He's aware of it, too: when he talks to Morgan about being offered the sheriff position, he admits that part of the reason he isn't sure about it is because he's afraid he'll revert to the manipulative asshole he used to be.)
* DaChief: He starts out as the day shift supervisor, then becomes director of the lab, and is later promoted to undersheriff of the entire department. By mid-Season 13 he's the new sheriff. He almost doesn't take it at first, because he's worried that he'll revert to the {{Jerkass}} he used to be.
* DiabolusExMachina: Supplies a rather nasty and completely out-of-nowhere one in [[spoiler:"Fracked"]]. (Though, granted, it's fairly clear that there's not much he can do.)
* HeroicBSOD: This is debatably the cause of his considering leaving his job in Season 13. He doesn't show any signs of being tired of his job until the corruption of the department and his shooting.
* JerkWithAHeartOfGold: He goes out of his way to make Grissom and the team look bad, particularly when investigating Gil and Sara's relationship after her kidnapping. However, he develops a "Heart of Gold" and becomes a ReasonableAuthorityFigure pretty nicely afterwards. His statement that he would've helped Grissom and Sara avoid any conflicts because of their relationship certainly sounded genuine, and he's been mostly a lot nicer to the team while still keeping his prickly attitude. Come the later seasons, he's been even better with Morgan around.
* JerkassHasAPoint: Despite being rude, unpleasant, and power-hungry, he is accurate about Grissom's leadership in Season 5, especially in the way he handled Sara. By that point, she has become very unprofessional, culminating in Sara mouthing off to Catherine (at the time, a superior) in front of coworkers and to Ecklie himself. He was absolutely right to suspend her, something Grissom would not have done due to their relationship.
* ObstructiveBureaucrat: He's extremely ambitious, and originally sees Grissom as competition. At different points, he would try and undermine the team's work.
* ParentalAbandonment: He left when Morgan was 14.
* RankUp: To Undersheriff and eventually Sheriff.
* ReasonableAuthorityFigure: When Nick is BuriedAlive, Ecklie pulls some strings to gather the ransom his kidnapper demands, and relations between him and the night shift have mostly thawed since then. Ecklie comes into his own as Asst. Director, where his talent for juggling the top brass and news media have proven to be an asset to the team.
** Once he's the new sheriff, he seems to have kept his reasonableness. The only time that he really pushes back against the team is when he's faced with having to give permission for his own daughter to be used as bait for a serial killer. A perfect example of his reasonable attitude is when Finn and Nick clash with a fire investigator at an arson scene. The investigator calls in Ecklie with "concerns" about their methods, and before passing any judgements, Ecklie hears Nick and Finn out and even takes his jacket off and helps them dig through a burnt-out building to prove their theory.
* TheRival: To Grissom, who deplores Ecklie's careerism.
* SmugSnake: Pre-"Grave Danger." He took utmost pleasure in seeing Grissom's team humiliated, and even worked to get Nick convicted of murder once purely out of spite.
* TakingTheBullet: [[spoiler:For his daughter when he gets gunned down in ''Homecoming''.]] It's possible that they had been aiming intentionally for him, but given that he [[spoiler: shot [=McKeen=]'s son]], it seems likely that Morgan was the target.

[[folder:Jeffrey [=McKeen=] ]]
[[quoteright:320:https://static.tvtropes.org/pmwiki/pub/images/mckeen-content_pic_5489.gif]]
->Played by: Creator/ConorOFarrell

* AmbitionIsEvil: Brass recalls that when he was made a detective, [=McKeen=] invited all of the new detectives over to his (suspiciously large) house for a barbecue. When Brass let him know that he wasn't such a careerist that could be bought like that, he was never invited again, and had to watch over the years as all the others at that barbecue were promoted above him.
* BigBad: [[spoiler:Of Season 8, the 12 finale, and the premiere of 13]].
* CluelessDetective: Doesn't always get or appreciate the abilities of the [=CSIs=] or what they do [[spoiler: which bites him in the ass when he tries to frame someone else for murder.]]
%%* CommanderContrarian
* ImplacableMan: Crashes his car at high speed when shot by his paranoid passenger, and drags himself away from the wreckage to bleed out...and lives,[[spoiler:[[SuicideByCop despite his best efforts]].]]
* JerkWithAHeartOfGold:[[spoiler:Subverted. He seems like that at times...until he [[MoralEventHorizon murders Warrick in cold blood.]]]]
* MightAsWellNotBeInPrisonAtAll: [[spoiler:"Homecoming" reveals that he's ''still'' running his criminal machinations from prison.]]
%%* TheMole
%%* ObstructiveBureaucrat
%%* ProfessionalButtKisser
%%* TheSheriff: Well, his title is Undersheriff.
* SuicideByCop: Attempts this with Nick, but Nick doesn't go through with it.

[[folder:Brian Mobley]]
!!Brian Mobley
[[quoteright:168:https://static.tvtropes.org/pmwiki/pub/images/5fd19cbf_d2be_4f9c_a379_5e8469329358.jpeg]]
->Played by: Creator/GlennMorshower

* DemotedToExtra: After being a major recurring character throughout the first season, he only appeares once in the second season before disappearing from the show entirely.
* WhatTheHellHero: He gives Grissom a major tongue lashing for turning his friend into a murder suspect for an apparent suicide, and wrongly, as it turned out, and forces him to issue a public apology.

[[folder:Rory Atwater]]
!!Rory Atwater
->Played by: Creator/XanderBerkeley

* DarkSecret: [[spoiler:He has an adult baby fetish.]]
* KillItWithFire: Narrowly averted when he is nearly blown up by a car bomb.

[[folder:Sherry Liston]]
!!Sherry Liston
->Played by: Creator/BarbaraEveHarris

* PutOnABus: Retires at the end of Season 12 out of shame over a corruption scandal.

[[folder:Chris Cavaliere]]
!!Chris Cavaliere
->Played by: Creator/JoseZuniga

* NightmareFetishist: He has a habit of taking photos of bizarre murders.
* RabidCop: He is very rough, once going as far as scaring a ''child'' into a confession.

[[folder:Cyrus Lockwood]]
!!Cyrus Lockwood
->Played by: Creator/JeffreyDSams

* KilledOffForReal: [[spoiler:Shot by a sniper during a bank robbery at the end of Season 3.]]

[[folder:Ray O'Riley]]
!!Ray O'Riley
->Played by: Creator/SkipOBrien

* BusCrash: [[spoiler:After disappearing without explanation after Season 4, Season 14 shows he was killed in the line of duty.]]
* ChuckCunninghamSyndrome: Disappears without explanation after Season 4. [[spoiler:Season 14 reveals he died in the line of duty offscreen.]]

[[folder:Frankie Leeds]]
->Played By: Creator/KateeSackhoff

[[folder:Carlos Moreno]]
->Played By: Creator/EnriqueMurciano

!! Other
[[folder:"Lady" Heather Kessler]]
[[quoteright:270:https://static.tvtropes.org/pmwiki/pub/images/kessler-wallpaper-82155_2.jpg]]
->Played by: Creator/MelindaClarke

* BrainsAndBondage: A licensed therapist...who also happens to run an S&M club.
* TheBusCameBack: Really never appears after William Petersen/Grissom stopped starring in the show, only appearing once for a case in Season 11. She returns as [[spoiler:a suspect yet again in one of the most massive cases to hit the show in ''C.S.I.'''s series finale.]]
* CollateralAngst: Not Heather herself, but in the GrandFinale [[spoiler: her toddler granddaughter is offhandedly revealed to have been killed in a car accident, which serves little purpose other than driving Heather across the DespairEventHorizon so she can be a murder suspect. She pulls the plug on her practice after her granddaughter dies, which helps set up the plot of the GrandFinale]].
* CreepyGood: For a creepy dominatrix lady she has a surprisingly good heart.
* {{Dominatrix}}: Her chosen profession.
* DarkIsNotEvil: Though she seems scary at first and is into some pretty dark stuff, she is definitely a good guy.
* DrivenToSuicide: Sort of. [[spoiler:In one episode, she hires a guy to kill her because she lost custody of her granddaughter.]] She lives, though.
* DropInCharacter: Cases have a weird way of tracing back to her.
* EthicalSlut: As befits her profession as a {{Dominatrix}}.
* LovableAlphaBitch: Emphasis on the "alpha" part as she's a {{Dominatrix}} by trade.
* TheMaidenNameDebate: Strangely enough, she apparently took her husband's name.
* MamaBear: Do ''not'' mess with her daughter. [[spoiler:She WILL perform her S&M routine on you to make it hurt before she kills you.]]
* OfCorsetsSexy: Wearing one when we first meet her.
* TheVamp: Used for good! In her third appearance, she sleeps with [[spoiler:Leon Sneller, the guy who killed her daughter]] to get evidence from him to give the team.
* WhipItGood: Used horrifyingly in "Pirates of the Third Reich" when [[spoiler:she captures Sneller, ties him to her car, and proceeds to try to whip him ''to death''. Grissom talks her out of it]].

[[folder:Sam Braun]]
->Played by: Creator/ScottWilson

* BigScrewedUpFamily: One son is a murderer, the other a heartless casino shark, and Sam himself might possibly be ''both''. [[WhiteSheep At least there's Catherine]].
* CainAndAbel: One of his sons kills the other out of jealousy.
* LukeIAmYourFather: We're informed he was an ex-boyfriend of Catherine's mother in prior episodes, so there's some {{foreshadowing}}.
%%*CorruptCorporateExecutive:
* DirtyOldMan: Definitely seems to prefer his women a full generation younger than him.
%%* DisappearedDad
* TheDon: Gives off this impression, but nothing's ever proven beyond this.
* DropInCharacter: It's apparently a small Vegas after all, because like Heather, his name comes up in a frankly absurd amount of cases. The difference, of course, being that while Heather usually takes the role of key witness, Sam being who he is is often the prime suspect.
* KarmaHoudini[=/=]NotProven: He is a suspect in a murder from decades ago, and Catherine wholeheartedly believes it was him, but there is another suspect to whom all the evidence seems to point, and Sam is never charged.
* KickTheDog: Organizing the bank robbery that gets [[spoiler:Detective Lockwood]] killed. Kept from being a full-on MoralEventHorizon-crossing by the fact that Sam doesn't ''intend'' anyone to die and the AxCrazy head robber foes off the rails, but the fact that he is willing to put innocent people [[spoiler:and lovable supporting cast members]] in a life-threatening situation purely for his own benefit is a pretty huge dick move.
* MoralityPet: Catherine. He also expresses genuine affection for Catherine's mother and Lindsay, but is not of seen interacting with them on-screen.
* PetTheDog: Hates himself for favoring his older son, leading to the jealous younger one killing him.
* RedHerring: No matter how good his motive or opportunity may be, he is ''always'' this.
%%* EvilOldFolks:
* VigilanteExecution: [[spoiler:...by the domestic partner of a man Braun had financially ruined]].

!! Criminals
[[folder:Paul Millander/The Bathtub Killer]]
->Played by: Creator/MattOToole

* BigBad: Of the pilot and a good chunk of the first two seasons.
* ChekhovsGun: The rubber hands he makes in his shop, the hand impression his father had made for him, and the ID his son makes for Grissom all turn out to be crucial to the case.
* TheChessmaster: Far smarter than the entire team ''put together''.
* DarkIsEvil: Before going on the run, he is the owner of a shop that sells ''seriously'' grisly Halloween props.
* EvilCounterpart: To Grissom; bonus points for being the first major ''C.S.I.'' nemesis to ever appear in the franchise.
* FreudianExcuse: He (or rather, "she" at the time) watched as his father was murdered and the death made to look like a suicide in his own home, and then his testimony was thrown out at the trial and the killers went free.
* HangingJudge: In his SecretIdentity.
* TheHeavy: For much of seasons 1 and 2.
* KarmaHoudini: Of a sort; he commits suicide, in the same way he killed his victims no less, to deny Grissom the satisfaction of sending him to jail.
* MommyIssues: His mother ostracized him after his operation. [[SelfMadeOrphan He repays her with a knife to the gut]].
* ThatOneCase: For Grissom. One of Millander's victims is the primary victim of the pilot episode.
* PetTheDog: Revealed posthumously; he honestly loved his adopted son.
* SecretIdentity: As a judge, complete with a family who know nothing of his murderous ways.
* SerialKiller: The series' first, and the setter of the standard for season-long arcs focusing on serial killers for both this and the other ''C.S.I.'' shows.
* SeriesContinuityError: A major plot point in his last episode is that he and his father have the same name... except that the elder Millander's name was given as "John" in a prior episode.
[[/folder]]

[[folder:The Miniature Killer/ [[spoiler:Natalie Davis]]]]
->Played By: [[spoiler:Creator/JessieCollins]]
* ArchEnemy: Quickly becomes this to Gil Grissom, [[spoiler:especially after she kidnaps Sara and leaves her for dead.]]
* AxCrazy: Key word: [[spoiler:Bleach. Say this to her or make any indication of the thing and you're dead.]]
* BigBad: Of Season 7 and the first episode of Season 8.
* TheBusCameBack: [[spoiler:Davis returns in one of Peterson's last episodes for a hearing about whether or not to transfer her to prison, which they do. She has worked over her bleach problem by this time.]]
* EideticMemory: Can recall the minutest details of a location after a short glance, which helps in making the miniatures.
* SiblingMurder: [[spoiler: As a child, she murdered her sister Chloe by pushing her out of a treehouse, because she was jealous of the attention her sister was receiving after her mother's death. This is also what causes her thing regarding bleach, as her father used it to clean her sister's blood off of the concrete.]]
* TheHeavy: Has this on Grissom long after [[spoiler:she's]] in prison, only matched by Millander and later Nate Haskell for Ray Langston.
* ThatOneCase: One of the most unique villains in the history of the ''C.S.I.'' franchise, [[spoiler:her]] entire M.O. with creating miniatures of future murder scenes then executing the scene to exacting standards became a hot topic both in the show and in real life for the 2006-2007 TV season.
* TheUnfavorite: [[spoiler: She was this as a kid, and it's implied her first kill was her older sister, in an attempt to finally get attention]].
* VillainousBreakdown: [[spoiler:When she's finally arrested, Grissom's attempt to force Sara's location out of her drops her into a catatonic state that requires her to be institutionalized.]]
[[/folder]]

[[folder:Nate Haskell/The Dick & Jane Killer]]
->Played by: Creator/BillIrwin
* AbusiveParent: His father was a drunk who would beat him and his mother.
* AllGirlsWantBadBoys: This monster has a "bride" fanclub.
%%* ArchEnemy: To Raymond Langston.
* AssholeVictim: After all he's done, it's hard to feel sorry for him after [[spoiler:Raymond Langston kills him.]]
* AttentionWhore: After being caught, he pleads not guilty, but later confesses when his defense claims that his crimes could only have been committed by multiple people working together. He is also the only murderer to accept the opportunity to speak to a class during a lecture.
* AxCrazy: As Brass puts it, "He's like the Joker from Batman, except without the laughs."
* BigBad: Of Langston's intro episode halfway through Season 9 (this was also Grissom's final regular story arc as a character until the series finale), and of Season 11. [[spoiler: His death is what ends Langston's character arc and his time at C.S.I.; Fishburne was asked to leave at that point and was replaced by Ted Danson.]]
* BlatantLies: While torturing his victims, he offers them a chance to survive. They never do.
* ChickMagnet: While in prison he gets proposed to a few times.
* ContrastingSequelAntagonist: To the earlier ArcVillain. The Miniature Killer was an isolated individual who was a forensic challenge to the [=CSIs=] to track down, while Nate is a psychological foe who is able to manipulate others into helping with his plans even behind bars. They also contrast physically: [[spoiler:Natalie is a young woman who looks and acts like a stiff breeze would blow her over, while Nate is a middle-aged man who can pose a physical threat.]]
* TheCorrupter: While other aspects of his M.O. change, he consistently takes pleasure in convincing others to become killers like him, whether it's his accomplices in the original Dick and Jane killings, or the [[spoiler: groupies who bust him out of custody and then murder each other]] or, in the end, [[spoiler: Ray Langston]].
* DarkAndTroubledPast: Was abused by his father and listened to him kill his mother when he was ''eight.''
* EnemyMine: Helps the CSI team find Dr. Jekyll. He uses the whole thing to ultimately set up his escape.
%%* FourEyesZeroSoul
* FreudianExcuse: His dad beat his mom to death and made him listen to her screams.
* IHaveYouNowMyPretty: Kidnaps Langston's ex-wife and rapes her, among other things.
* InTheBack: Stabs Langston in the kidney area in the 10th season finale.
* TheHeavy: This guy's specter hangs over the C.S.I.s from his first appearance to [[spoiler: just past his death when his saga results in Langston being forced out and Catherine and Nick getting demoted back to their original positions from when Grissom dealt with Haskell; this leads to Catherine's own exit from the lab later.]]
* KillAndReplace: "Nate Haskell" turns out to have been the name of his first victim, a traveling salesman whose identity he stole. His real name is Warner Thorpe.
* {{Sadist}}: Brass compares him to the ''Joker!'' Need we say any more?
* SevenDeadlySins:
** Pride: See AttentionWhore above.
** Lust: Takes sadistic pleasure in corrupting others and making them suffer.
* TortureTechnician: And how! At one point he kidnaps Langston's ex wife and puts her in a torture device that would not be out of place in ''Franchise/{{Hellraiser}}'' films.
* YouHaveOutlivedYourUsefulness: Kills his final MonsterFangirl, after most of the others kill one another.
[[/folder]]

[[folder:Dr. Jekyll/ Chef Charlie Dimasa]]
->Played by: Creator/MattRoss
* ArchEnemy: To Ray in Season 10; he loses this position back to Nate Haskell [[spoiler:after he's killed.]]
* BigBad: Of Season 10.
* TheHeavy: Ray is really troubled by this suspect, especially when they meet in a hospital and Jekyll steals Ray's ID card, which he mails back along with prosciutto that has a Jane Doe number of an earlier botched victim on it; [[NiceJobFixingItVillain this is how they identify him when they match DNA he left]] to [[spoiler:his father's septic appendix]], which is found in his second victim (and the first one he actually killed) earlier in the season.
* MeatgrinderSurgery: Subverted; he takes great care when performing his surgeries/murders, which does not help the case at all.
* NonIndicativeName: He is named after [[TheStrangeCaseOfDrJekyllAndMrHyde Dr. Henry Jekyll]] even though the killer does not have an [[JekyllAndHyde evil split personality]] and Jekyll is supposed to be the good one. Furthermore, while most versions of Jekyll are medicinal doctors, none of them are surgeons who performed gruesome operations on innocent people.
* SecretIdentity: [[spoiler:Dr. Jekyll turns out to not be a doctor at all, but a cook in a luxurious Italian restaurant who had to drop out of medical school to assist his father. He does well as a chef, but does not take the whole thing well at all, hence his literal butchering surgery on the season's victims.]]
* ThatOneCase: Jekyll's odd surgeries (starting with someone who was already dead, but moving on to actual murder thru surgery after the C.S.I. trilogy) stump Langston and Dr. Robbins throughout the show's 10th anniversary, with Langston taking his work home. They [[DealWithTheDevil eventually have to]] [[EnemyMine enlist Nate Haskell]], the BigBad of Ray's introductory episodes, to finally bullseye Jekyll, but this move [[NiceJobBreakingItHero leads to the Season 11 plotline]] and the events that end in Langston and Catherine's departures from the crime lab.
* VillainousBreakdown: [[spoiler:When Langston and Stokes find him, he finally turns on the Mr. Hyde persona for the first and only time by grabbing a shotgun, blowing the head off a cop, shooting up his restaurant and trapping everyone there.]]
[[/folder]]

[[folder:Jason [=McCann=]]]
->Played by: Music/JustinBieber
* ArchEnemy: Temporarily becomes one to Nick via communications and bombs until he is killed.
* AssholeVictim: Jason has already killed a bomb technician friend of the team's and injured Vartaan by the time he goes on a short-lived shooting rampage against a police roadblock with Nick and Brass.
[[/folder]]

!! Lab Technicians

[[folder:David Hodges]]
[[quoteright:183:https://static.tvtropes.org/pmwiki/pub/images/David_Hodges_1526.jpg]]
->Played by: Creator/WallaceLangham

* BornLucky: But only on a single day: April 7th. It's his lucky day. On this day, ''nothing'' has ever gone wrong for him, ever. In "Lab Rats," he takes advantage of it being his lucky day to help crack a case that even Grissom couldn't figure out.
* BrilliantButLazy: Unlike most Lab Rat characters on the CSI shows, Hodges is quite content to remain indoors and hates going into the field.
%%* BunnyEarsLawyer
%%* DeadpanSnarker
* DirtyCop: Averted. [[spoiler:The first episode of the revival uncovers evidence that, during his time at the lab, he faked results by the truckload, putting any conviction resulting from said fake lab results in jeopardy. Sara believes it to be a FrameUp, but the DA wants Hodges arrested anyway, and every one of the cases he was involved in is now under scrutiny. Sara, Gil, and the new CSI team manage to fully clear his name by the finale, thus saving the crime lab's integrity as well.]]
* HiddenDepths: Among other things he's a big sci-fi geek, with an undying love for "Astro Quest" (fictional couterpart of ''Series/StarTrekTheOriginalSeries'').
* LargeHam: Has his moments, but the "Astro Quest" episode (and the dream sequences that have Hodges as TheCaptain of the ShowWithinAShow) are pretty much a chance for Langham to unleash his inner Creator/WilliamShatner in a homage to "''The Gamesters Of Triskelion."''
* MommasBoy: He is living with his mother when he first starts working at the lab. When she finally appears on-screen, we learn that she's a surprisingly attractive and classy lady, and far from the typical MyBelovedSmother that most mothers involved in this trope are.
* TheNoseKnows: Has an incredibly accurate sense of smell. In "In Vino Veritas," he leans into a wine barrel that had held a corpse for a few days and deeply inhales, grossing out a co-worker. He explains that he can determine the source of the wine from the various ingredients he detects...over the smell of decomp. In "The Theory of Everything", Catherine has him get down on the floor of a victim's bedroom and smell the carpet for evidence, as he possesses the genetic makeup that lets him smell the presence of cyanide.
* PetTheDog[=/=]EstablishingCharacterMoment: For the first couple of his seasons, he is portrayed as a through-and-through {{Jerkass}} ProfessionalButtKisser with no redeeming qualities whom all his co-workers hate. In Season 7, however, he gets a surprising amount of CharacterDevelopment in a scene where he has to break bad news to a victim's family, and he's portrayed as a sympathetic character ever since and even joins the main cast. He even gets a wife and by the end of season 1 of the revival, a child.
%% * PromotionToOpeningTitles
%% * TheReliableOne
* SmallNameBigEgo: He acts like he's much more important than everyone else. Can occasionally cross into InsufferableGenius.
* WhyDidItHaveToBeSnakes: He has an inordinate fear of birds.

[[folder:Wendy Simms]]
[[quoteright:175:https://static.tvtropes.org/pmwiki/pub/images/csiwendysimms.jpg]]
->Played by: Creator/LizVassey
%%* TheLabRat: Although she wants to become a "field mouse."
* MsFanservice: Particularly in Hodges' fantasies of her. In one she's only wearing a ''bikini''.
%%* PromotionToOpeningTitles
* PutOnABus: In universe: Left for Portland's lab.

[[folder:Mandy Webster]]
->Played by: Creator/SheeriRappaport
%%* DeadpanSnarker
* ReallyGetsAround: Some of her comments in the lab rats' DayInTheLimelight episodes hint at this.
%%* TheLabRat

[[folder:Archie Johnson]]
->Played by: Creator/ArchieKao
* AsianAndNerdy: He's a computer analyst and a Franchise/StarTrek geek. Could be {{subverted}} since he does have 'cool' hobbies like surfing and snowboarding.
%%* TheLabRat

[[folder:Henry Andrews]]
[[quoteright:175:https://static.tvtropes.org/pmwiki/pub/images/csihenryandrews.jpg]]
->Played by: Creator/JonWellner
* ButtMonkey: "Appendicitement" and "Field Mice" are the biggest examples.
%%* CannotTellAJoke
%%* TheLabRat
%%* PromotionToOpeningTitles: Wellner gets this beginning in Season 13.

[[folder:Bobby Dawson]]
->Played by: Creator/GeraldMcCullouch
%%* ButtMonkey: In Hodges' "Lab Rats" board game.
%%* GunNut
%%* TheLabRat

[[folder:Ronnie Litra]]
->Played by: Creator/EricStonestreet
%%* BigFun
* ChuckCunninghamSyndrome: Just vanishes after Season 4 or so.
%%* TheLabRat

!! Police

[[folder:Captain James "Jim" Brass]]
[[quoteright:230:https://static.tvtropes.org/pmwiki/pub/images/Brass-CSI-Guilfoyle-230x300_5789.jpg]]
->Played by: Creator/PaulGuilfoyle

* AllOfTheOtherReindeer: "A Bullet Runs Through It," where the other cops shun him at the dead officer's funeral.
* BerserkButton: Bad fathers, likely because he wishes ''he'' [[MyGreatestFailure could've been a better one]].
* BlindPeopleWearSunglasses: In the revival, he’s wearing them before revealing his eyes which were damaged in an attack. He’s not completely blind but can’t see very well.
%%* CoolOldGuy
* DeadpanSnarker: On Vegas' staggeringly-high murder rate: "We're very competitive!"
* DirtyCop : Originally a big subversion of this, stating how he refuses to be bought or get dirty, but drifts into that territory as of the end of season 11. [[spoiler:He covers for Ray when Ray kills Nate Haskell, and is reluctant to help catch a killer who was killing other killers.]]
* EtTuBrute: In "A Bullet Runs Through It," he feels this way when one by one, all of the other officers walk away from him at the dead officer's funeral.
* HandicappedBadass: He's in his 70s and half-blind come the revival series, but it opens with him kicking and killing the ass of a man sent to kill him.
* HiddenDisdainReveal: Despite trying to help his daughter, even knowing she isn't actually his, every time she gets herself into trouble. [[spoiler:After a crime of hers gets her mother killed, he flatly tells her that she killed the only person who cared about her.]]
%%zce* JerkWithAHeartOfGold: Eventually mellows out into this.
* MrExposition: He's the man who gives both the team and the audience information on the latest victim of the week.
* OutrankingYourJob: Spends a lot of time personally investigating crime scenes and chasing down suspects for a police captain.
* ParentalIssues: He still loves his daughter despite knowing that she's not genetically his. Her...not so much, to the point that when Brass is shot he gives power of attorney to Grissom rather than to her. Another contributing factor is probably that she has been addicted to drugs and worked as a prostitute for a time, so it would be understandable for Brass to doubt her judgment in general.
* PutOnABus: Takes a leave of absence for season 15 [[spoiler: after his daughter fakes her kidnapping with the help of a boyfriend, gets Brody involved and almost kills her, kills the boyfriend, and kills her mother (whom she didn't expect to come to Las Vegas) because she would have recognized the boyfriend. Amazingly Brass is helping her with her trial.]]
** TheBusCameBack: Comes back for the finale, and for a few appearances in the revival.
* SemperFi: Vietnam Marine vet.

[[folder:Sofia Curtis]]
[[quoteright:215:https://static.tvtropes.org/pmwiki/pub/images/sofia-curtis5903757600ml_4738.jpg]]
->Played by: Creator/LouiseLombard

* ActionGirl: Oh yeah. And given her profession, it's absolutely necessary for her survival.
* ChuckCunninghamSyndrome[=/=]PutOnABus: Is a semi regular for three seasons, a regular character in one season, and then vanishes without a trace, or explanation.
** TheBusCameBack: Returns late in Season 11. [[RankUp She's Deputy Chief now.]]
%%* FairCop
* HeroicBSOD: In "A Bullet Runs Through It," when she believes she shot a fellow cop.
%%* MrExposition: Basically, a female Jim Brass.
* RankUp: She starts out as his subordinate but ends up being Captian Brass' boss.

[[folder:Conrad Ecklie]]
[[quoteright:256:https://static.tvtropes.org/pmwiki/pub/images/ecklie-imgres-78_6171.jpeg]]
->Played by: Creator/MarcVann

* ADayInTheLimelight: The B-plot of one episode features Ecklie handling the investigation himself when the main characters are unavailable.
* AmbitionIsEvil: The real reason he is such an ass to Grissom and the team was because he thinks that Grissom has the same ambitions he does. Once he realizes that Grissom and the team won't keep him from fulfilling his goals, he eases off considerably.
** His behavior in the Season 14 episode "Consumed," though, suggests that running for sheriff may cause him to relapse.
* BigBad: Arguably, of Season 5. He never does anything illegal, but his antagonistic actions drive the overarching plot of that season.
* CharacterDevelopment: A fairly significant example of this. He's almost a completely different person now than he was in season 1. He makes a pretty seamless transition from {{Jerkass}} to JerkWithAHeartOfGold. After 13 seasons he's still a bit nasty at times, but he has the respect of the team and the department as a whole, and he has absolutely become a ReasonableAuthorityFigure. (He's aware of it, too: when he talks to Morgan about being offered the sheriff position, he admits that part of the reason he isn't sure about it is because he's afraid he'll revert to the manipulative asshole he used to be.)
* DaChief: He starts out as the day shift supervisor, then becomes director of the lab, and is later promoted to undersheriff of the entire department. By mid-Season 13 he's the new sheriff. He almost doesn't take it at first, because he's worried that he'll revert to the {{Jerkass}} he used to be.
* DiabolusExMachina: Supplies a rather nasty and completely out-of-nowhere one in [[spoiler:"Fracked"]]. (Though, granted, it's fairly clear that there's not much he can do.)
* HeroicBSOD: This is debatably the cause of his considering leaving his job in Season 13. He doesn't show any signs of being tired of his job until the corruption of the department and his shooting.
* JerkWithAHeartOfGold: He goes out of his way to make Grissom and the team look bad, particularly when investigating Gil and Sara's relationship after her kidnapping. However, he develops a "Heart of Gold" and becomes a ReasonableAuthorityFigure pretty nicely afterwards. His statement that he would've helped Grissom and Sara avoid any conflicts because of their relationship certainly sounded genuine, and he's been mostly a lot nicer to the team while still keeping his prickly attitude. Come the later seasons, he's been even better with Morgan around.
* JerkassHasAPoint: Despite being rude, unpleasant, and power-hungry, he is accurate about Grissom's leadership in Season 5, especially in the way he handled Sara. By that point, she has become very unprofessional, culminating in Sara mouthing off to Catherine (at the time, a superior) in front of coworkers and to Ecklie himself. He was absolutely right to suspend her, something Grissom would not have done due to their relationship.
* ObstructiveBureaucrat: He's extremely ambitious, and originally sees Grissom as competition. At different points, he would try and undermine the team's work.
* ParentalAbandonment: He left when Morgan was 14.
* RankUp: To Undersheriff and eventually Sheriff.
* ReasonableAuthorityFigure: When Nick is BuriedAlive, Ecklie pulls some strings to gather the ransom his kidnapper demands, and relations between him and the night shift have mostly thawed since then. Ecklie comes into his own as Asst. Director, where his talent for juggling the top brass and news media have proven to be an asset to the team.
** Once he's the new sheriff, he seems to have kept his reasonableness. The only time that he really pushes back against the team is when he's faced with having to give permission for his own daughter to be used as bait for a serial killer. A perfect example of his reasonable attitude is when Finn and Nick clash with a fire investigator at an arson scene. The investigator calls in Ecklie with "concerns" about their methods, and before passing any judgements, Ecklie hears Nick and Finn out and even takes his jacket off and helps them dig through a burnt-out building to prove their theory.
* TheRival: To Grissom, who deplores Ecklie's careerism.
* SmugSnake: Pre-"Grave Danger." He took utmost pleasure in seeing Grissom's team humiliated, and even worked to get Nick convicted of murder once purely out of spite.
* TakingTheBullet: [[spoiler:For his daughter when he gets gunned down in ''Homecoming''.]] It's possible that they had been aiming intentionally for him, but given that he [[spoiler: shot [=McKeen=]'s son]], it seems likely that Morgan was the target.

[[folder:Jeffrey [=McKeen=] ]]
[[quoteright:320:https://static.tvtropes.org/pmwiki/pub/images/mckeen-content_pic_5489.gif]]
->Played by: Creator/ConorOFarrell

* AmbitionIsEvil: Brass recalls that when he was made a detective, [=McKeen=] invited all of the new detectives over to his (suspiciously large) house for a barbecue. When Brass let him know that he wasn't such a careerist that could be bought like that, he was never invited again, and had to watch over the years as all the others at that barbecue were promoted above him.
* BigBad: [[spoiler:Of Season 8, the 12 finale, and the premiere of 13]].
* CluelessDetective: Doesn't always get or appreciate the abilities of the [=CSIs=] or what they do [[spoiler: which bites him in the ass when he tries to frame someone else for murder.]]
%%* CommanderContrarian
* ImplacableMan: Crashes his car at high speed when shot by his paranoid passenger, and drags himself away from the wreckage to bleed out...and lives,[[spoiler:[[SuicideByCop despite his best efforts]].]]
* JerkWithAHeartOfGold:[[spoiler:Subverted. He seems like that at times...until he [[MoralEventHorizon murders Warrick in cold blood.]]]]
* MightAsWellNotBeInPrisonAtAll: [[spoiler:"Homecoming" reveals that he's ''still'' running his criminal machinations from prison.]]
%%* TheMole
%%* ObstructiveBureaucrat
%%* ProfessionalButtKisser
%%* TheSheriff: Well, his title is Undersheriff.
* SuicideByCop: Attempts this with Nick, but Nick doesn't go through with it.

[[folder:Brian Mobley]]
!!Brian Mobley
[[quoteright:168:https://static.tvtropes.org/pmwiki/pub/images/5fd19cbf_d2be_4f9c_a379_5e8469329358.jpeg]]
->Played by: Creator/GlennMorshower

* DemotedToExtra: After being a major recurring character throughout the first season, he only appeares once in the second season before disappearing from the show entirely.
* WhatTheHellHero: He gives Grissom a major tongue lashing for turning his friend into a murder suspect for an apparent suicide, and wrongly, as it turned out, and forces him to issue a public apology.

[[folder:Rory Atwater]]
!!Rory Atwater
->Played by: Creator/XanderBerkeley

* DarkSecret: [[spoiler:He has an adult baby fetish.]]
* KillItWithFire: Narrowly averted when he is nearly blown up by a car bomb.

[[folder:Sherry Liston]]
!!Sherry Liston
->Played by: Creator/BarbaraEveHarris

* PutOnABus: Retires at the end of Season 12 out of shame over a corruption scandal.

[[folder:Chris Cavaliere]]
!!Chris Cavaliere
->Played by: Creator/JoseZuniga

* NightmareFetishist: He has a habit of taking photos of bizarre murders.
* RabidCop: He is very rough, once going as far as scaring a ''child'' into a confession.

[[folder:Cyrus Lockwood]]
!!Cyrus Lockwood
->Played by: Creator/JeffreyDSams

* KilledOffForReal: [[spoiler:Shot by a sniper during a bank robbery at the end of Season 3.]]

[[folder:Ray O'Riley]]
!!Ray O'Riley
->Played by: Creator/SkipOBrien

* BusCrash: [[spoiler:After disappearing without explanation after Season 4, Season 14 shows he was killed in the line of duty.]]
* ChuckCunninghamSyndrome: Disappears without explanation after Season 4. [[spoiler:Season 14 reveals he died in the line of duty offscreen.]]

[[folder:Frankie Leeds]]
->Played By: Creator/KateeSackhoff

[[folder:Carlos Moreno]]
->Played By: Creator/EnriqueMurciano

!! Other
[[folder:"Lady" Heather Kessler]]
[[quoteright:270:https://static.tvtropes.org/pmwiki/pub/images/kessler-wallpaper-82155_2.jpg]]
->Played by: Creator/MelindaClarke

* BrainsAndBondage: A licensed therapist...who also happens to run an S&M club.
* TheBusCameBack: Really never appears after William Petersen/Grissom stopped starring in the show, only appearing once for a case in Season 11. She returns as [[spoiler:a suspect yet again in one of the most massive cases to hit the show in ''C.S.I.'''s series finale.]]
* CollateralAngst: Not Heather herself, but in the GrandFinale [[spoiler: her toddler granddaughter is offhandedly revealed to have been killed in a car accident, which serves little purpose other than driving Heather across the DespairEventHorizon so she can be a murder suspect. She pulls the plug on her practice after her granddaughter dies, which helps set up the plot of the GrandFinale]].
* CreepyGood: For a creepy dominatrix lady she has a surprisingly good heart.
* {{Dominatrix}}: Her chosen profession.
* DarkIsNotEvil: Though she seems scary at first and is into some pretty dark stuff, she is definitely a good guy.
* DrivenToSuicide: Sort of. [[spoiler:In one episode, she hires a guy to kill her because she lost custody of her granddaughter.]] She lives, though.
* DropInCharacter: Cases have a weird way of tracing back to her.
* EthicalSlut: As befits her profession as a {{Dominatrix}}.
* LovableAlphaBitch: Emphasis on the "alpha" part as she's a {{Dominatrix}} by trade.
* TheMaidenNameDebate: Strangely enough, she apparently took her husband's name.
* MamaBear: Do ''not'' mess with her daughter. [[spoiler:She WILL perform her S&M routine on you to make it hurt before she kills you.]]
* OfCorsetsSexy: Wearing one when we first meet her.
* TheVamp: Used for good! In her third appearance, she sleeps with [[spoiler:Leon Sneller, the guy who killed her daughter]] to get evidence from him to give the team.
* WhipItGood: Used horrifyingly in "Pirates of the Third Reich" when [[spoiler:she captures Sneller, ties him to her car, and proceeds to try to whip him ''to death''. Grissom talks her out of it]].

[[folder:Sam Braun]]
->Played by: Creator/ScottWilson

* BigScrewedUpFamily: One son is a murderer, the other a heartless casino shark, and Sam himself might possibly be ''both''. [[WhiteSheep At least there's Catherine]].
* CainAndAbel: One of his sons kills the other out of jealousy.
* LukeIAmYourFather: We're informed he was an ex-boyfriend of Catherine's mother in prior episodes, so there's some {{foreshadowing}}.
%%*CorruptCorporateExecutive:
* DirtyOldMan: Definitely seems to prefer his women a full generation younger than him.
%%* DisappearedDad
* TheDon: Gives off this impression, but nothing's ever proven beyond this.
* DropInCharacter: It's apparently a small Vegas after all, because like Heather, his name comes up in a frankly absurd amount of cases. The difference, of course, being that while Heather usually takes the role of key witness, Sam being who he is is often the prime suspect.
* KarmaHoudini[=/=]NotProven: He is a suspect in a murder from decades ago, and Catherine wholeheartedly believes it was him, but there is another suspect to whom all the evidence seems to point, and Sam is never charged.
* KickTheDog: Organizing the bank robbery that gets [[spoiler:Detective Lockwood]] killed. Kept from being a full-on MoralEventHorizon-crossing by the fact that Sam doesn't ''intend'' anyone to die and the AxCrazy head robber foes off the rails, but the fact that he is willing to put innocent people [[spoiler:and lovable supporting cast members]] in a life-threatening situation purely for his own benefit is a pretty huge dick move.
* MoralityPet: Catherine. He also expresses genuine affection for Catherine's mother and Lindsay, but is not of seen interacting with them on-screen.
* PetTheDog: Hates himself for favoring his older son, leading to the jealous younger one killing him.
* RedHerring: No matter how good his motive or opportunity may be, he is ''always'' this.
%%* EvilOldFolks:
* VigilanteExecution: [[spoiler:...by the domestic partner of a man Braun had financially ruined]].

!! Criminals
[[folder:Paul Millander/The Bathtub Killer]]
->Played by: Creator/MattOToole

* BigBad: Of the pilot and a good chunk of the first two seasons.
* ChekhovsGun: The rubber hands he makes in his shop, the hand impression his father had made for him, and the ID his son makes for Grissom all turn out to be crucial to the case.
* TheChessmaster: Far smarter than the entire team ''put together''.
* DarkIsEvil: Before going on the run, he is the owner of a shop that sells ''seriously'' grisly Halloween props.
* EvilCounterpart: To Grissom; bonus points for being the first major ''C.S.I.'' nemesis to ever appear in the franchise.
* FreudianExcuse: He (or rather, "she" at the time) watched as his father was murdered and the death made to look like a suicide in his own home, and then his testimony was thrown out at the trial and the killers went free.
* HangingJudge: In his SecretIdentity.
* TheHeavy: For much of seasons 1 and 2.
* KarmaHoudini: Of a sort; he commits suicide, in the same way he killed his victims no less, to deny Grissom the satisfaction of sending him to jail.
* MommyIssues: His mother ostracized him after his operation. [[SelfMadeOrphan He repays her with a knife to the gut]].
* ThatOneCase: For Grissom. One of Millander's victims is the primary victim of the pilot episode.
* PetTheDog: Revealed posthumously; he honestly loved his adopted son.
* SecretIdentity: As a judge, complete with a family who know nothing of his murderous ways.
* SerialKiller: The series' first, and the setter of the standard for season-long arcs focusing on serial killers for both this and the other ''C.S.I.'' shows.
* SeriesContinuityError: A major plot point in his last episode is that he and his father have the same name... except that the elder Millander's name was given as "John" in a prior episode.

[[folder:The Miniature Killer/ [[spoiler:Natalie Davis]]]]
->Played By: [[spoiler:Creator/JessieCollins]]
* ArchEnemy: Quickly becomes this to Gil Grissom, [[spoiler:especially after she kidnaps Sara and leaves her for dead.]]
* AxCrazy: Key word: [[spoiler:Bleach. Say this to her or make any indication of the thing and you're dead.]]
* BigBad: Of Season 7 and the first episode of Season 8.
* TheBusCameBack: [[spoiler:Davis returns in one of Peterson's last episodes for a hearing about whether or not to transfer her to prison, which they do. She has worked over her bleach problem by this time.]]
* EideticMemory: Can recall the minutest details of a location after a short glance, which helps in making the miniatures.
* SiblingMurder: [[spoiler: As a child, she murdered her sister Chloe by pushing her out of a treehouse, because she was jealous of the attention her sister was receiving after her mother's death. This is also what causes her thing regarding bleach, as her father used it to clean her sister's blood off of the concrete.]]
* TheHeavy: Has this on Grissom long after [[spoiler:she's]] in prison, only matched by Millander and later Nate Haskell for Ray Langston.
* ThatOneCase: One of the most unique villains in the history of the ''C.S.I.'' franchise, [[spoiler:her]] entire M.O. with creating miniatures of future murder scenes then executing the scene to exacting standards became a hot topic both in the show and in real life for the 2006-2007 TV season.
* TheUnfavorite: [[spoiler: She was this as a kid, and it's implied her first kill was her older sister, in an attempt to finally get attention]].
* VillainousBreakdown: [[spoiler:When she's finally arrested, Grissom's attempt to force Sara's location out of her drops her into a catatonic state that requires her to be institutionalized.]]

[[folder:Nate Haskell/The Dick & Jane Killer]]
->Played by: Creator/BillIrwin
* AbusiveParent: His father was a drunk who would beat him and his mother.
* AllGirlsWantBadBoys: This monster has a "bride" fanclub.
%%* ArchEnemy: To Raymond Langston.
* AssholeVictim: After all he's done, it's hard to feel sorry for him after [[spoiler:Raymond Langston kills him.]]
* AttentionWhore: After being caught, he pleads not guilty, but later confesses when his defense claims that his crimes could only have been committed by multiple people working together. He is also the only murderer to accept the opportunity to speak to a class during a lecture.
* AxCrazy: As Brass puts it, "He's like the Joker from Batman, except without the laughs."
* BigBad: Of Langston's intro episode halfway through Season 9 (this was also Grissom's final regular story arc as a character until the series finale), and of Season 11. [[spoiler: His death is what ends Langston's character arc and his time at C.S.I.; Fishburne was asked to leave at that point and was replaced by Ted Danson.]]
* BlatantLies: While torturing his victims, he offers them a chance to survive. They never do.
* ChickMagnet: While in prison he gets proposed to a few times.
* ContrastingSequelAntagonist: To the earlier ArcVillain. The Miniature Killer was an isolated individual who was a forensic challenge to the [=CSIs=] to track down, while Nate is a psychological foe who is able to manipulate others into helping with his plans even behind bars. They also contrast physically: [[spoiler:Natalie is a young woman who looks and acts like a stiff breeze would blow her over, while Nate is a middle-aged man who can pose a physical threat.]]
* TheCorrupter: While other aspects of his M.O. change, he consistently takes pleasure in convincing others to become killers like him, whether it's his accomplices in the original Dick and Jane killings, or the [[spoiler: groupies who bust him out of custody and then murder each other]] or, in the end, [[spoiler: Ray Langston]].
* DarkAndTroubledPast: Was abused by his father and listened to him kill his mother when he was ''eight.''
* EnemyMine: Helps the CSI team find Dr. Jekyll. He uses the whole thing to ultimately set up his escape.
%%* FourEyesZeroSoul
* FreudianExcuse: His dad beat his mom to death and made him listen to her screams.
* IHaveYouNowMyPretty: Kidnaps Langston's ex-wife and rapes her, among other things.
* InTheBack: Stabs Langston in the kidney area in the 10th season finale.
* TheHeavy: This guy's specter hangs over the C.S.I.s from his first appearance to [[spoiler: just past his death when his saga results in Langston being forced out and Catherine and Nick getting demoted back to their original positions from when Grissom dealt with Haskell; this leads to Catherine's own exit from the lab later.]]
* KillAndReplace: "Nate Haskell" turns out to have been the name of his first victim, a traveling salesman whose identity he stole. His real name is Warner Thorpe.
* {{Sadist}}: Brass compares him to the ''Joker!'' Need we say any more?
* SevenDeadlySins:
** Pride: See AttentionWhore above.
** Lust: Takes sadistic pleasure in corrupting others and making them suffer.
* TortureTechnician: And how! At one point he kidnaps Langston's ex wife and puts her in a torture device that would not be out of place in ''Franchise/{{Hellraiser}}'' films.
* YouHaveOutlivedYourUsefulness: Kills his final MonsterFangirl, after most of the others kill one another.

[[folder:Dr. Jekyll/ Chef Charlie Dimasa]]
->Played by: Creator/MattRoss
* ArchEnemy: To Ray in Season 10; he loses this position back to Nate Haskell [[spoiler:after he's killed.]]
* BigBad: Of Season 10.
* TheHeavy: Ray is really troubled by this suspect, especially when they meet in a hospital and Jekyll steals Ray's ID card, which he mails back along with prosciutto that has a Jane Doe number of an earlier botched victim on it; [[NiceJobFixingItVillain this is how they identify him when they match DNA he left]] to [[spoiler:his father's septic appendix]], which is found in his second victim (and the first one he actually killed) earlier in the season.
* MeatgrinderSurgery: Subverted; he takes great care when performing his surgeries/murders, which does not help the case at all.
* NonIndicativeName: He is named after [[TheStrangeCaseOfDrJekyllAndMrHyde Dr. Henry Jekyll]] even though the killer does not have an [[JekyllAndHyde evil split personality]] and Jekyll is supposed to be the good one. Furthermore, while most versions of Jekyll are medicinal doctors, none of them are surgeons who performed gruesome operations on innocent people.
* SecretIdentity: [[spoiler:Dr. Jekyll turns out to not be a doctor at all, but a cook in a luxurious Italian restaurant who had to drop out of medical school to assist his father. He does well as a chef, but does not take the whole thing well at all, hence his literal butchering surgery on the season's victims.]]
* ThatOneCase: Jekyll's odd surgeries (starting with someone who was already dead, but moving on to actual murder thru surgery after the C.S.I. trilogy) stump Langston and Dr. Robbins throughout the show's 10th anniversary, with Langston taking his work home. They [[DealWithTheDevil eventually have to]] [[EnemyMine enlist Nate Haskell]], the BigBad of Ray's introductory episodes, to finally bullseye Jekyll, but this move [[NiceJobBreakingItHero leads to the Season 11 plotline]] and the events that end in Langston and Catherine's departures from the crime lab.
* VillainousBreakdown: [[spoiler:When Langston and Stokes find him, he finally turns on the Mr. Hyde persona for the first and only time by grabbing a shotgun, blowing the head off a cop, shooting up his restaurant and trapping everyone there.]]

[[folder:Jason [=McCann=]]]
->Played by: Music/JustinBieber
* ArchEnemy: Temporarily becomes one to Nick via communications and bombs until he is killed.
* AssholeVictim: Jason has already killed a bomb technician friend of the team's and injured Vartaan by the time he goes on a short-lived shooting rampage against a police roadblock with Nick and Brass.

* DirtyCop: Averted. [[spoiler:The first episode of the revival uncovers evidence that, during his time at the lab, he faked results by the truckload, putting any conviction resulting from said fake lab results in jeopardy. Sara believes it to be a FrameUp, but the DA wants Hodges arrested anyway, and every one of the cases he was involved in is now under scrutiny.]]

* AmbiguousDisorder: He displays the combination of [[TheSmartGuy extremely high intelligence]] and [[NoSocialSkills extremely low social skills]] that is stereotypically associated with Asperger's syndrome and other forms of high-functioning autism, but nothing is ever stated for certain.

* ChuckCunninghamSyndrome/PutOnABus: Is a semi regular for three seasons, a regular character in one season, and then vanishes without a trace, or explanation.

* BrotherChuck: Is a semi regular for three seasons, a regular character in one season, and then vanishes without a trace, or explanation.

* HotScientist:
--> '''Greg:''' ''That's'' Ecklie's daughter?

%%* {{Jerkass}} In Season 1.
** JerkWithAHeartOfGold: Eventually mellows out into this.

%%* {{Jerkass}}: Definitely one pre-Season 6. Goes out of his way to make Grissom and the team look bad, particularly when investigating Gil and Sara's relationship after her kidnapping.
** JerkWithAHeartOfGold: Developed into one, and a ReasonableAuthorityFigure, pretty nicely afterwards. His statement that he would've helped Grissom and Sara avoid any conflicts because of their relationship certainly sounded genuine, and he's been mostly a lot nicer to the team while still keeping his prickly attitude. Come the later seasons, he's been even better with Morgan around.
** JerkassHasAPoint: Despite being rude, unpleasant, and power-hungry, he is accurate about Grissom's leadership in Season 5, especially in the way he handled Sara. By that point, she has become very unprofessional, culminating in Sara mouthing off to Catherine (at the time, a superior) in front of coworkers and to Ecklie himself. He was absolutely right to suspend her, something Grissom would not have done due to their relationship.

* PlayingGertrude: Melinda Clarke was 32 when she first played the role of a character who, given her daughter's age, is probably intended to be in her early forties. [[spoiler: Melinda wasn't even 40 by the time Heather became a grandmother in the show.]]

* AscendedFanboy: From "CSI Wannabe" to actual CSI. He started working as the DNA tech before going into the field.

* {{Flanderization}} In regards to his [[TheStoic stoicism]]. In the first season, he was prone to bouts of anger (once slapping a coffee pot out of Ecklie's hand, enraged) and happiness (even--gasp--smiling! With teeth and all!). By Season 3, his character was shaped into being level-headed at all times, even in normal conversation. Justifiable in that he starts to retreat emotionally during his struggle with his hearing loss.

[[folder:Dr. Raymond Langston]]

[[folder:Captain Jim Brass]]

* TheProfessor: Is teaching college just before he take the job as a [=CSI=].
* PutOnABus: After killing Haskell, [[spoiler:he is discharged from CSI by IAB and sent back to the east coast with his former ex-wife. He's mentioned once in the Season 12 opener, but is completely dropped from the series afterwards and essentially completing his character arc. He's one of a handful of living characters that doesn't return for the series finale.]]
* TokenMinority