[[quoteright:350:http://static.tvtropes.org/pmwiki/pub/images/csi-las-vegas.jpg]]
[[caption-width-right:350:The "classic" cast.]]

->''"Concentrate on what cannot lie -- the evidence."''
-->-- '''Gil Grissom'''

''CSI: Crime Scene Investigation'' (sometimes unofficially referred to as ''CSI: Las Vegas'' when differentiating the shows in the franchise, mostly abroad where ''CSI: Miami'' made the franchise popular) is a highly successful TV show (2000-present) about a group of graveyard-shift crime scene investigators in Las Vegas led originally by enigmatic scientist Gil Grissom, then, following his departure, by ex-stripper and single mother Catherine Willows, and now, by quirky scientist DB Russell. Initially touted as a show where the evidence was the main character and the actual characters were little more than flat stereotypes with "quirks" added almost as an afterthought, the series has progressed over its thirteen seasons to make the characters a little more rounded and include more of their personal lives and histories in the story lines. It has also moved on from a fairly straightforward forensics approach to more high-tech approaches that aren't necessarily possible in real life, requiring some degree of suspension of disbelief from the viewer. CSI runs into the Road of Trials (Part of Hero's Journey) many time throughout the series. CSI as a forensic/ mystery show has continued for many years, holding on very strongly and getting more interesting as time goes by.

[[FollowTheLeader Influenced a great many subsequent programs]]; most directly, it inspired its producer, JerryBruckheimer, to try and replicate this success with ''Series/WithoutATrace'' and ''Series/ColdCase'' (both in the same verse). It also followed in ''Franchise/LawAndOrder'''s 'franchise' footsteps, with ''{{CSI Miami}}'' (''[[MemeticMutation Yeeeeeeeaaaahh!]]''), ''{{CSI NY}}'' and the newly ordered ''{{CSI Cyber}}''. As of end of the 2013-14 season, there are 746 total episodes of ''CSI'', ''{{Series/CSI Miami}}'' (''[[RunningGag Yeeeeeeeaaaaahhhh!]]''), and ''{{CSI NY}}'', not including books, comic books, and video games related to the franchise. Please note, however, that it is not the oldest of the current crop of forensic shows, a title held by British show ''Series/SilentWitness''.

Gil Grissom's frequent one-liners right before the opening credits or an ad break are a well known example of a QuipToBlack, although [[Series/CSIMiami Horatio Caine's]] versions are perhaps the best known - mostly due to the heaping layer of cheese added to them. Pretty much established the NecroCam, which it uses as a device to re-enact for the viewers every single gruesome detail that can be extracted from a crime scene, and every theory it spawns.

The uncanny effectiveness of the show's AppliedPhlebotinum has caused some to suspect that it's not actually set in the present day, but, rather, TwentyMinutesIntoTheFuture (on-screen dates, though, put it in the PresentDay).

The show (and its spinoffs) have given rise to what legal professionals call 'TheCSIEffect': the necessity of compressing what would normally be months worth of delicate and time-consuming lab work into a 40-minute television episode causes similarly unrealistic expectations in potential real-world jurors. As a result, the uninformed juror will assume that what they see on the show is happening ''as it actually occurs'', as opposed to being fabricated and accelerated for television.

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!!This show provides examples of:

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[[folder:A-D]]
* AbsenteeActor: William Petersen's absence in a series of episodes brought in Liev Schreiber as Petersen took a break from ''CSI'' while he starred in a play called ''Dublin Carol'', a twist on Dickens' ''Literature/AChristmasCarol'' in Providence, R.I. The episode "Gum Drops" was changed when Petersen left town due to a death in the family. The focuses of the episode changed from Grissom to Nick being certain Cassie was alive. "Genetic Disorder" was changed from a Nick-centric episode to a Greg-centric one when George Eads left town for his father's funeral.
** On "Gum Drops", given what Nick himself had [[BuriedAlive been through]] and how he could empathize with her plight, was probably an improvement. "Genetic Disorder" becoming Greg-centric can be seen as an improvement as well, as it shows how much Greg has matured as a person and as an investigator over the past decade. He ultimately refuses to jump to conclusions, waits to get official results, and calls other characters out for assuming Doc Robbins is guilty of something (Hodges and Brass). Compare to a season 1 episode where Greg actually does jump to a conclusion about a couple, and he is found wrong about it.
* AccidentalHero: Witnesses who unknowingly obtain or provide useful evidence have made life infinitely easier for the [=CSI=]s on multiple occasions.
* AdultFear: One episode had two boys who went missing and the main suspect is a pedophile. It didn't help when the team had to enlist his help to try to find the boys and he began to [[NightmareFuel describe in detail]] to Grissom how he would lure a child to him by gaining their trust. Another suspect was one of the boys' abusive grandfather. Imagine you were the father of that man, forced to leave your son with him because the grandfather was the only one available to look after your son. And failed.
* AffablyEvil: Doctor Dave, the serial-killing dentist from the episode "Sweet Jane". He has a pleasant chat with Catherine about loving his work (dentistry, not serial killing), and how he especially takes care to make a child's first trip to the dentist the least frightening and painful as possible. And when she confronts him about his crimes, not only does he never once deny that he is, in fact, a murderer, he describes the killings in the same affectionate tone that he just described trying to make a trip to the dentist less scary for kids. Ned Beatty's note-perfect performance was a complete blend of utterly friendly and utterly scary-creepy.
** To push this even farther, when Catherine is trying to mix the putty for his dental impression, he remarks that she's not quite doing it right and does both the mixing and the impression himself; again, as politely as one could possibly be while fessing up to being a serial killer.
* AffectionateParody: In one episode, to DarkerAndEdgier [[Series/BattlestarGalacticaReimagined reimaginings]] of [[Franchise/StarTrek classic sci-fi shows]].
* AlienAutopsy: Subverted in "Viva Las Vegas", when the "alien" was identified as a costumed human with a medical condition that made him ''look'' a bit like a Grey.
* AllGirlsWantBadBoys: [[SerialKiller Nate Haskel]] despite the numerous women he's killed and raped has fairly large group of women obsessed with him, even he acknowledges that he's a chick magnet making him an in-universe DracoInLeatherPants. His harem even go so far as to [[spoiler: breaking him out of prison after stabbing Langston and after being found guilty for all his past murders]].
* AllPsychologyIsFreudian:
** Episode "4x4"
--->'''Greg Sanders:''' No matter how hard you work to get big, there's always someone bigger.
--->'''Sara Sidle:''' It could be what keeps them going. Like Freud said, "Anatomy is destiny".
--->'''Greg Sanders:''' What do you think Freud would have to say about one of these being the murder weapon?
** Episode "Fur And Loathing"
--->'''Grissom:''' Well, Freud said that the only unusual sexual behavior was to have none at all.
** Episode "Lab Rats"
--->'''Hodges:''' Freud's theory on the uncanny raises the point that as children we want the doll to come to life. But as adults, we are terrified by the idea. The doll could represent the uncanny that is feared. The Sandman."
** Episode "King Baby" had a victim with an infantilism fetish (a fetish for pretending to be a baby and being nursed). At the end of the episode we meet the victim's mother, who mentions she never breastfed her son, believing it would make her soft.
* AmbiguousDisorder: Gil Grissom is all sorts of quirky and odd, a bit too literal, not exactly social, but not exactly unsocial either, kinda fumbling...how much so, it just depends on what the script calls for.
* AndStarring: Paul Guilfoyle gets an "And", Robert David Hall a "With". LaurenceFishburne - because he is, well, Laurence Fishburne - goes first in the order. Ditto with Ted Danson.
* AntagonisticOffspring: Ellie Brass, in all of her appearances.
** Especially in [[spoiler:the season 14 premiere, "The Devil and D.B. Russell," where it turns out she's the mastermind behind the killings who also offs her mother.]]
* AppliedPhlebotinum
* ArtisticLicenseBiology: The series plays fast and loose with various aspects of biology, particularly on the subject of fingerprints, which aren't necessarily left as easily or on as many surfaces as the show would have one believe.
** One CGI montage in "Grave Danger" shows fire ants injecting venom through their ''bites''. Real ants only bite to get hold and then inject venom through their abdomen stings, like bees and wasps.
* AscendedExtra: Nate Haskell, the Dick and Jane Killer.
* ATeamMontage: As the various forensic specialists build a case.
* AutopsySnackTime: Given a TakeThat when Doc Robbins irately says of a long retired coroner (who missed something in the original autopsy of someone who was to be exhumed) that he "held a scalpel in one hand and a hot dog in the other."
* BaitAndSwitch: In "Loco Motives", one suspect suffered from a string of incredibly bad luck; after he was caught, he related the incident to one where he got his daughter a puppy, and later backed out of the driveway. The investigator expects him to say he killed the puppy. He replies, [[CrossesTheLineTwice "No, I ran over my daughter. Ten years later, and she still walks funny."]] Catherine is listening in and barely stifles her laughter.
* BeAsUnhelpfulAsPossible: When a member of CSI intimates that the husband is always the first suspect when a wife is murdered, the husband's response is typically "You think I did this? This interview is over!" - inadvertently doing [[http://www.boingboing.net/2008/07/28/law-prof-and-cop-agr.html the pragmatic thing]]. (But again, TruthInTelevision; police ''expect'' ordinary people to get angry when accused of crimes they didn't commit.)
* BeastlyBloodsports: "Lying Down With Dogs", where a wealthy humanitarian was found dead and then found to be involved in dogfighting.
* BeepingComputers: Not so much used as ''abused''.
* BerserkButton: In addition to this trope being the motive for crime, Grissom himself states that he absolutely can't stand spouse abusers, drug dealers, and people who hurt children.
** On a wider scale, each investigator has their own. Catherine can't handle cases that even tangentially involve kids without going nuts, Sara can't deal with spousal abusers, etc....
* BigBlackout: "CSI Unplugged".
* BigEater: Deconstructed in an episode where the team investigates an obese man that apparently ate himself to death. What looks like a silly comedic episode at first gets a really sad ending when it is revealed that the victim was a mentally ill person with Prader-Willi Syndrome, a genetic disorder that causes insatiable hunger among other symptoms, and that he had been let loose by an irresponsible caretaker who wanted to use him to win an eating contest.
* BilingualPun: probably unintentonal, there's an episode where a fat man is killed and he has the surname Brenner which means 'burning' in Norwegian, in the same episode there was a murder fire.
* BitterAlmonds: Subverted: a big show is made of only 20% of people being able to smell cyanide, and there is another, more useful, symptom. So many forensic miracles on this show, and yet this trick doesn't work!
* BlackBlood / AlienBlood: In Season Eight's "The Theory of Everything", a number of dead people wound up with ''avocado-green blood''.
* BlackComedy: Pretty much a given in a show about police officers and [=CSIs=] dealing with death on a daily basis.
* BlondeBrunetteRedhead: Brody, Sara, and Catherine within the show [[spoiler: until Catherine left]]; among the female leads across the spinoffs there's [[Series/CSIMiami blonde Calleigh]] and [[CSINewYork brunettes Stella and Danville]].
** Male leads: Las Vegas has [[CoolOldGuy white-haired]] Grissom and DB; [[Series/CSINewYork brunet Mac]] and [[Series/CSIMiami redhead Horatio]].
* BloodIsTheNewBlack: "Bad to the Bone", a particularly nasty murderer is caught almost immediately when he casually walks into a diner to wash his hands after beating a man to death.
* ABloodyMess: In "Alter Boys", a suspected blood stain turns out to be red sauce.
* BodyInABreadbox: Every two or three episodes, a corpse turns up someplace ''really'' odd.
* BodybagTrick: Catherine and D.B. use this trick to get themselves smuggled back into the lab when a hit team is looking for them in "Willows in the Wind".
* BornLucky: For one single day, David Hodges [[http://www.youtube.com/watch?v=kYMXka7CEMg was the luckiest guy on earth]]. His lucky day even allowed Grissom to gain important insight on the Miniature Killer case.
* TheBoxingEpisode: "Fight Night"
* BrainsAndBondage: Grissom's one-time potential love interest Lady Heather was an intelligent woman who ran an S&M club.
* BrainBleach: Common throughout various characters, be it core cast or those involved in the cases. Nick and Ray seems to want some when they find out just exactly WHAT those vacuum-packed panties were after seeing one show attendee demonstrate in Season Ten's "The Panty Sniffer".
** Definitely a few people's reaction to the episode "Blood Drops". Anyone who has seen the episode knows why, anyone who hasn't should consider themselves lucky.
* BreatherEpisode: Several, usually with the death turning out to be accidental.
* BrokenBird: Sara Sidle has a pretty serious case of this.
* BrokenPedestal: Catherine's mentor.
* BulletTime: Commendably, they waited until [[Film/TheMatrix Morpheus]] had thoroughly settled in before showing a bullet-time extravaganza (complete with TheMenInBlack!).
* BunnyEarsLawyer: At least half the cast is messed up in some way or another despite being generally competent at their job, but the title has to go to Hodges, who started out so mentally unbalanced that not only would he never be allowed to work with law enforcement in any capacity in the real world, he probably wouldn't even be allowed outdoors without some kind of supervision. He has settled down somewhat as time has gone on, but he still has his moments.
* BuriedAlive: Nick in "Grave Danger".
** And Laura Garas in the third episode.
* CaliforniaDoubling
* CallBack: Catherine's [[spoiler: final scene]] includes a reference to the "King Kong on cocaine" line she used to describe the joy of the job to Holly Gribbs, way back in the pilot.
* CallingTheOldManOut: Catherine, after Lindsey is kidnapped, and a few other times as well.
* CallItKarma: A low-budget porn director slashes the throat of an actress that had been revealed to be HIV-positive and thus unable to make more porn films. Her blood spills all over his face, some of it getting inside him through the eyes, and he gets AIDS himself as a result.
* CanonImmigrant: Sqweegel, who originated in Anthony Zuiker's digital novel "Level 26".
* CantGetAwayWithNuthin: Catherine visits the Highball after work once. Naturally, a murder occurs there, and she gets chewed out by ''everyone'' for failing to mention that she went there for a drink until they haul a SmugSnake suspect in and he recognizes her. Her daughter and mother also join in the shunning, and the episode ends with Gil giving her the silent treatment, followed by a curt lecture on how an 'act of omission' makes her just like a common perpetrator.
* CameraAbuse: In the episode, "Felonius Monk", the camera is shot by a paintball round.
* CantGetInTroubleForNuthin: In one episode, the Victim Of The Week in the B plot turns out to have been a homeless man. He tried to get sent to jail (for free food and shelter) by punching a police officer. Said officer realized what he was doing and left him handcuffed, apparently failing to realize this would lead to his death.
* CarpetRolledCorpse: In "CSI Unplugged", the BodyOfTheWeek is rolled up in a rug and carried out of the house before being dumped in the garden with note pinned to it with a knife.
* TheCaseOf: Found in the season eight episode, "The Case of the Cross-Dressing Carp".
* CelebrityParadox: In an episode of the early seasons, we can see the Series/MythBusters making a cameo as extras. Fast forward to season 11 episode 2, there is a character exclaiming "What am I one of those Mythbuster guys? I don't know."
* CelebrityStar: Many episodes feature at least one.
* ChuckCunninghamSyndrome: Detective Sofia Curtis was a recurring character during seasons 5 and 6, and actress Louise Lombard was a main cast member in season 7. But come season 8, Lombard left the series and, two seasons later, Sofia's disappearance has yet to be explained.
** [[http://www.tvguide.com/News/Louise-Lombard-CSI-1030475.aspx Until now...]]
* CityOfAdventure: It IS Las Vegas after all.
* ClassReunion: In "Dead of Class", Dave attends his class reunion nad has all of the typical run-ins with his former classmates. Then the festivities are disrupted when the former prom queen is murdered.
* CoffinContraband: In "Maid Man", the ultimate goal of the killer is a cache of mob money hidden inside a burial niche in a mausoleum.
* TheCollectorOfTheStrange: All the creepy crawlies in Grissom's office. There's also an irradiated fetal pig.
* ColorCodedForYourConvenience: In "Long Road Home", a fingerprint is rendered visible on a document known to have been handled by a woman called "Tangerine". Even before her photo shows up on the [=AFIS=] computer screen, it's clear to viewers that it's hers, because the cyanoacrylate mist turns the print ''tangerine'' orange.
* ColorMotif: The original ''CSI'' has a lot of brown that evokes the desert setting of Las Vegas. ''CSI: Miami'' has a lot of orange and yellow to evoke the bright, sunny semi-tropics of Miami. ''CSI NY'' has blues and grays to evoke the gritty nature of the big city.
* ComatoseCanary: Used straight on the original show; subverted on ''CSI: New York''.
* ComedicSociopathy: Hodges, who would make a fine MagnificentBastard if he weren't so grotesquely inept at everything that didn't involve forensic science.
* CommutingOnABus: Sara's right on the line between this and TheBusCameBack. She's listed as a regular, but not in every single episode.
* ConspiracyTheorist: All of the victims and suspects in "Leapin' Lizards".
* ConsultingAConvictedKiller: Langston seeks the help of his nemesis, serial killer Nate Haskell, to catch the "Dr. Jekyl Killer". [[spoiler: He isn't really that helpful and mostly just messes them around. His actual plan was to goad a guard into [[ShockCollar shocking him]] as to fall and break his own glasses... and using the broken arms from said glasses to stab Langston through the bars of his holding cell.]]
** [[spoiler: Well, he pointed them to the restaurant where they found the link between all of the murders and from there were led to the actual killer, so in that sense he was ''very'' helpful. But after that he just strung them along waiting for his chance to attack Ray, and milking his apparent knowledge for all it was worth.]]
* {{Contortionist}}: "Sqweegel" can contort himself enough to fit into the spare tire compartment of a car. Instead of sticking to performance, he's expanded applications of this to murdering unsuspecting victims.
* CoolOldGuy: DB.
* CoolestClubEver: The setting of many of the episodes.
* CopKiller: Several examples in spirit, though not always in letter since the [=CSIs=] aren't actually cops in this show.
** The RedShirt who gets killed when Warrick leaves her alone at a crime scene in the pilot.
** A random officer who's killed outside a burger joint...by another cop who claims it was an accident, but might have had a grudge ([[spoiler: it was dark and said cop was losing his vision]]).
** [[spoiler: Warrick Brown]] was killed at the end of a later season by [[spoiler: [[TheMole The Undersheriff]]]].
* CouldHaveAvoidedThisPlot: In "Anatomy of a Lye", a young hot-shot attorney tried to cover up what appeared to be a DUI hit-and-run when he allowed the pedestrian he hit to die while lodged in his windshield, then soaked his body in lye and buried him in a playground. But as it turned out, the pedestrian [[DrivenToSuicide jumped out in front of his car in a suicide attempt]]. If he had just stopped and called 9-1-1, he probably would've gotten off scot free, or at worst with just a DUI charge.
-->'''Sara:''' You were off the hook...\\
'''Grissom:''' ...until you let him die.
* CowboyCop
* CrammingTheCoffin: In "For Gedda", the team investigates the murder of a man who was stuffed in an occupied coffin. The victim ends up being someone Warrick is familiar with.
* CrazyCatLady: The victim in "Cats in the Cradle".
* CrazyPrepared: Langston. This ends up working to his detriment.
* CreepyChild: [[spoiler:"Bad Words"]]. A given when said child is a pyromaniac.
** Also the creepy girl from "Unusual Suspect" and "Goodbye and Good Luck".
%% CrowningMomentOfAwesome goes on the Awesome/CSI page, not here.
* CreepyTwins / SiblingYinYang: [[spoiler: The Gig Harbor Killer, unemployed and lived alone on a boat, and his wealthy real estate wiz brother (they were adopted by separate families). It's implied they were already partners for the GHK murders and that the wealthy twin is using the "copycat" crime scenes to spring his brother. Additionally the elaborately staged crime scenes have hidden Gemini symbols (spots of blood and threads made of human body parts form the constellation, two crimes scenes are on properties belonging to sister companies named after Castor and Pollux).]]
* CutApart: The fifth season finale uses this trope to deal a YourPrincessIsInAnotherCastle moment to a rescue operation.
* DarkSecret: Often the motive for many of the crimes.
* ADateWithRosiePalms: A teenage girl disappeared, and while investigating the house, the team discovers one of her nightgowns is covered in her brother's semen. They suspect that he had something to do with the disappearance until Nick takes the boy aside and privately asks him about this trope. Turns out, the brother was doing the deed in the bathroom and simply grabbed the first item on the top of the clothes hamper, leading to his embarrassment when this is revealed.
* DeadMansChest:
** In one episode, a spurned lover stuffs his ex-boyfriend's body in a trunk, which is kept in private storage. Problem is, the body won't fit, so he cuts off the head and leaves it in a car which is then stolen.
** In "Long Road Home", a body is hidden in a gera box containing a set of drums and dumped in alley.
* DeadlyRoadTrip: It involved a particularly dead-eyed gang of juvenile delinquents who beat up tourists ForTheEvulz, knowing that as juveniles they would face relatively short sentences if caught.
* DeadpanSnarker: Count on one (or more) of the cast members making a {{pun}} right after the discovery of the body and just before the opening credits.
* DeathDealer: The first VictimOfTheWeek in "Last Woman Standing" is killed when his throat is slashed open by a thrown playing card.
* DeathInTheClouds: "Unfriendly Skies".
* DefectiveDetective: Hardly anyone on the cast ''doesn't'' have some personal demon: Grissom's nerdiness and hearing-loss scare, Sara's mother killing her abusive father and ending up in an institution, Catherine's work keeping her away from family, Brass' estranged daughter, Warrick's gambling addiction, etc.
* DirtyCop: Vega, [=McQuaid=], and one other FBI agent.
* DisappearingBox: A woman seems to disappear for real in "Abra-Cadaver".
* DoNotCallMePaul: D.B. Russell. Nobody calls him Diebenkorn. And Julie, who prefers 'Finn', which is short for Finlay.
* DoubleAesop: Frequently done with a guest character, to apply the moral of their story to a longer-running established storyline and/or to one of the main cast.
* DownerEnding: "Alter Boys", "Homebodies", "Fracked", "Let it Bleed", and of course "For Gedda". Really, any episode where they [[NotProven can't prove the suspect did anything wrong]] could be considered this.
** "Bittersweet" had the culprit turn out to be a [[spoiler:surviving victim from a serial killer that was imprinted on by her violator and ended up murdering her victims in the same fashion.]]
** Just five episodes later, in "Crime After Crime," it's revealed that [[spoiler:fairly major recurring character Detective Vega has gone {{Vigilante Execution}}er, and he commits SuicideByCop]].
** "Trends With Benefits" seemed like it was heading this way. [[spoiler: The rapist professor's victim didn't want to press charges and the other students he had sex with consented]] but somehow [[spoiler: word gets out and the professor is suspended]].
* DyingDream: [[spoiler: Working Stiffs: "I knew it wouldn't work..."]]
[[/folder]]

[[folder:E-L]]
* EagleEyeDetection: Grissom and Catherine provided the page image at one point.
* EarlyInstallmentWeirdness: In the first few episodes of the first season, Brass is openly antagonistic with the [=CSIs=] and acts as a cynical bureaucratic {{foil}} to the more idealistic forensic scientists (specifically Grissom). This completely changed with the ninth episode "Unfriendly Skies" which featured Brass helping the [=CSIs=] solve a case with no mention of their previously unfriendly relationship, and by the end of the season the character had been {{Retconned}} into the most important ally that the [=CSIs=] had in the police department. Also, the early episodes did not feature the UnnaturallyBlueLighting that would later define the visual style of the lab.
* EdibleAmmunition: The frozen meat bullets one perpetrator used to shoot his victim.
* EducationThroughPyrotechnics: Complete with [[Series/MythBusters Adam and Jamie]] looking on in one episode.
* ElevatorFailure: Hodges and Henry get stuck when all of Vegas loses power.
* EmbarrassingFirstName: 'Diebenkorn' Russell, aka D.B.
* EnfantTerrible: An 8-year-old not only kills and steals from the victim in [[spoiler: "Cats in the Cradle"]], but also tries to incriminate her mother when cornered by the evidence.
** The 12-year-old in "Go to Hell" is even worse.
** The young killer in "Unusual Suspects" and "Goodbye And Goodluck".
** Music/JustinBieber's character, a teenage RightWingMilitiaFanatic out to [[RevengeBeforeReason avenge his brother]] who deliberately almost blows up Stokes, traps Willows, her detective boyfriend, and a [[TooCoolToLive cool bomb tech]] in a warehouse lined with explosive boobytraps, and convince another adult to go along with all this. Oh, [[ArsonMurderAndJayWalking and he was a brat on the set]].
* EnhanceButton: They once used a reflection in a young girl's eye in a photo to get an image of a location of where the picture was taking at (a boat).
** A particularly {{egregious}} example happened when they showed off a 3D crime scene scanner. Such a device does actually exist, using a laser to create a 3D image of an area, but they then used the computer to ''lift the body off the bed to look at the stains on the sheets underneath it''. It's the equivalent of taking an ordinary photographic image and being able to "strip away" the skin and muscles to get an image of not just the structure of the person's bones, but what ''color'' they are.
*** Theoretically, this ''could'' work, if they'd separately scanned the pattern of bloodstains into the computer, then had it apply this pattern onto the sheets of the 3D simulation. If so, it's a legitimate way to demonstrate how the stains were distributed underneath the body, once the sheets had been removed as evidence.
* EnemyWithin: Ray, and his struggle not to give into his dark side.
* EverybodyDidIt: "Unfriendly Skies", though it was actually self-defense; the delusional victim was trying, probably unintentionally, to bring down the plane.
* EverybodyIsSingle: Or at least, ''almost'' everyone. Gil and Sara are now married. Warrick ''was'' married but the marriage fell apart. DB is married and mentions it at least OnceAnEpisode. Doc Robbins is also married, as is his assistant, David Phillips.
* EvilCounterpart: Grissom used to hold fellow entomologist Dr. Mark Thayer in high esteem, and they even co-authored a scientific paper once. Since then, however, Dr. Thayer has become what Grissom describes as a "hired gun", selling his services to the highest bidder. When Thayer's testimony for the defense threatens to derail a high-profile murder trial, the D.A.'s office asks Grissom to try and refute Thayer's findings. Grissom eventually discovers that [[spoiler:Thayer deliberately doctored the evidence to get the results he wanted to present, which would have given the jury cause for reasonable doubt.]] After Grissom explains his findings on the stand and destroys Thayer's testimony, an enraged Thayer comes up to him and accuses him of attacking his integrity. As they're arguing, the D.A. comes up to them and [[spoiler:orders Thayer's arrest on charges of perjury and obstruction of justice.]]
** To a lesser extent, Gil's counterpart on Day Shift, Conrad Ecklie. He tended to choose the "convenient" answer rather than the correct one and was more interested in advancing his career than finding justice.
* ExtraYExtraViolent: Referenced in one episode; a couple knows their son has this condition and constantly treats him with suspicion because of it. [[spoiler:When their daughter accidentally kills their other son by pushing him down the stairs, she claims he did it on purpose; this is what actually turned him violent.]]
* EyesAreUnbreakable
* FairCop: Yowza! [[ActionGirl Sofia Curtis]], Vartann, [[BlackDudeDiesFirst Lockwood]], Sofia Curtis, that lady cop Nick dated for a second in Season 1, [[FakeAmerican Sofia Curtis]]...
* FakingTheDead: DB and Catherine come back to the morgue in body bags to escape the hitmen who are after them.
* FatalFlaw: Warrick's gambling problem. Grissom's hearing impairment also counts, though that was corrected with surgery at the end of Season three. Ray's inherited violence tendencies.
* AFatherToHisMen: Grissom's markedly paternal leadership style, most visible with Greg, Nick and Warrick -- [[spoiler:especially right before Warrick gets killed, and afterwards.]] DB is getting into this now. His group meetings are "family meetings".
* FelonyMurder
* FingerInTheMail: One episode featured a man who had found the cut-off index finger of his mistress in her apartment. Later, [[spoiler:they find the body]] and it is revealed that [[spoiler:it was the man himself who had killed her. To avoid suspicion of the murder, he staged it as a kidnapping gone wrong.]]
* FollowTheLeader: The show precipitated a host of forensic science shows, even to the point that shows not inherently about forensics now spend more time on the subject (e.g. the medical examiner on ''Series/LawAndOrderSpecialVictimsUnit'').
* FoodAndAnimalAttraction: Exploited in one episode; a woman going through a messy divorce wipes bacon grease on her hands to spite her husband after agreeing that his beloved dog would live with whomever it "chose". [[spoiler: He then proceeds to attempt to sneak in and replace the dog with another, so she shoots him. The sound of the gunshot causes the replacement dog to go berserk and tear her throat out.]]
* FoodPorn: The dishes in "Last Supper", until chefs guess [[TheSecretOfLongPorkPies the secret ingredient]] ("It was supposed to be ''kangaroo''!").
* ForensicDrama
* FromTheLatinIntroDucere: It had one when Grissom investigated the death of a man who had Down's syndrome. After catching the murderer, Grissom calls back to an earlier conversation where the murderer called the victim a "retard" (Grissom corrected him, of course) and informs him that "retard" means "to hinder", so the killer's life "just got retarded".
* GambitPileup: "Suckers".
* TheGamblingAddict: Warrick.
* GameOfNerds: Grissom is a baseball fan.
* GoodColorsEvilColors: Vampire {{LARP}}ers have [[RedEyesTakeWarning red eyes]] while werewolves have [[SupernaturalGoldEyes yellow eyes]] in "Blood Moon".
* {{Gorn}}: The [[FanNickname TMI-cam]].
* GPSEvidence: Often. As an example: in the season five finale, "Grave Danger", Grissom, Entomologist Extraordinaire, determines Nick's location from the ants in his box, since fire ants can only be found in nurseries in Nevada, which means that the soil... you can figure out the rest.
** [[IncrediblyLamePun Punningly]] used in the episode "Fracked", with literal GPS data.
* HappilyMarried: Gil and Sara, though it's a long distance marriage. D.B., the first CSI to start on the show with a wife and family.
* HardWorkMontage: This show does this to show the characters doing the hard work of forensic investigation at the lab. In the episode "I Like to Watch", they do some LampshadeHanging: Hodges looks forward to a certain test, as he thinks it will be good material for the documentary crew currently in the lab. Nick points out that the test takes six hours, to which Hodges remarks that "When they cut it together, it'll only take thirty seconds." It takes thirty seconds. Also known as "Microscope montage".
* HazardousWater: Murder in a cloudy swimming pool.
* HeelFaceTurn: Although he was originally introduced as an antagonistic character, Conrad Ecklie has since undergone considerable CharacterDevelopment (especially in season 12, in which his estranged daughter moves from L.A. to join the team) and become a much more sympathetic character.
* HeroicBystander: Civilians have helped the [=CSIs=] on multiple occasions either by finding evidence that helps break a case or even by catching the criminals in a chase.
* HighSchoolRejects: The standard stoners and malcontents that are always the first suspects.
* HoistByHisOwnPetard: A woman that was planning to poison her boss and ex-lover with ricin accidentally spills it over her pens. Not bad, if it wasn't for the fact she had an habit of biting her pens...
* HollywoodExorcism: "Go to Hell". [[JustifiedTrope Justified]], since the guy performing it is a self-made "priest" with no actual church affiliation and little [[HolierThanThou idea]] [[ChristianityIsCatholic about everything]].
* HollywoodNerd: '''EVERYONE'''. One of them is even supposed to be an ex-stripper!
* HollywoodScience: Never take anything presented as ''science'' on any of the episodes as even remotely factual unless you verify it first. In fact, the illusion of accuracy in this manner is [[http://www.cspo.org/documents/csieffectheinrick.pdf causing some issues...]]
** In the earlier seasons, the show prided itself on portraying science relatively accurately (though ''Miami'' didn't); even the seemingly-nonsensical "acoustic archaeology" that solves the case in "Committed" has factual basis. This changed in later on, the most {{egregious}} example likely being a computer program that can apparently delete things out of photographs to see what's behind them.
* {{Homage}}: "Blood Moon"'s opening opts for [[Series/TrueBlood sex and violence]] rather than [[Literature/{{Twilight}} sparkly]] vampires and werewolves.
* HotScientist: Practically all of the [=CSIs=] and the lab techs.
* HumiliationConga: Langston's first day is a non-villain example.
* IAmNotMyFather: Ray tried desperately not to become his.
* ImagineSpot: In the Season 13 premiere, we see DB imagining [[spoiler: his granddaughter and Flynn in the morgue, him killing [=McKeen=] (the corrupt cop who orchestrated his granddaughter's kidnapping), and his wife getting fed up with his disturbing job and leaving him]].
* IncessantMusicMadness: One case involves a garotted musician. [[spoiler:Turns out he was killed by an angry neighbour who couldn't stand the noise.]]
* InitialismTitle
* InTheBlood: Langston fears he may have a genetically inherited [[BloodKnight violent streak]] from his father, which is the toned-down version of his original backstory where he fears he may become a ''serial killer''. In an interesting subversion, the person he tells the story of his father (minus the In The Blood part) is the adopted son of the infamous serial killer Judge Mason/Paul Millander, to show that being a serial killer isn't passed down to people who are neither related to nor shown that kind of behavior, despite what his weary mother fears.
** Played straight with Haskell: [[spoiler: His father has been killing for years and his victims include Haskell's mother.]]
* TheIntern: Greg, when he decides to leave behind life in the lab to become a CSI.
* InterserviceRivalry: Regular LVPD vs the crime lab. The LVPD often see the lab team as a bunch of science nerds. Even Brass was not happy being assigned there in the beginning.
** The baseball ep had the LVPD playing another group.
* ItsPersonal: Seasons often start and/or end with an "It's Personal" episode.
** In the episode "Random Acts of Violence", Warrick is processing the scene of a suburban drive-by shooting, at which a young child has been shot and killed. Upon discovering that the child's father is a close friend (known to be an admirable and honorable person generally), Warrick does his best to comfort the grieving father. Aware of this connection, Grissom arrives and checks on his colleague:
--->'''Grissom''': You going to be able to handle this?
--->'''Warrick''': ...I want this case.
** In early seasons, even if there weren't a direct relationship between the investigators and the criminals the nature of the crime would often make the investigator ''take it personally'' themselves. For instance: domestic abuse, or overall violence towards women? Sara would sympathize. Broken marriages, or mothers (especially the working kind)? Catherine. Damaged childhoods? Nicky. Grissom himself explicitly stated that drug dealers and people who harm children make him furious.
--->"You prey on innocent children, and you think we came all the way out here to bust you for possession, you dumb punk?!"
* ItWorksBetterWithBullets: In "Forget Me Not", Ronald Basderic attempts to shoot Sara only to find that Detective Crawford had swapped the clip from his gun for one loaded with blanks when he searched him earlier.
* JackTheRipoff: "The Execution of Catherine Willows".
* JoggersFindDeath
* TheJudge: A few episodes center around the [=CSIs=] actually appearing in court, so naturally this trope applies.
* JustAFleshWound: Catherine is shot in the side, cauterized with a curling iron, and is still able to keep running from the bad guys.
* JustifiedCriminal: Eventually subverted--the bank robber claims he's doing it for his family, but he's lying.
* JustOneLittleMistake: How most perpetrators get caught.
** A subversion in the episode "Killer":
-->'''SympatheticMurderer''': So where did I screw up?
-->'''Grissom''': You killed two people.
* KarmaHoudini: A typical ''CSI'' DownerEnding will likely involve one of these, the most horrifying examples being Kelly James from "Homebodies", a robber and rapist who not only walks, but [[spoiler:murders the only person who could finger him]]; the [[spoiler:gas company]] from "Fracked", who drove an old farmer to suicide after poisoning all his animals; and Gina from "Bittersweet", who served five years in prison as an accessory to murder, only for new evidence to come to light that ''she'' was the dominant partner, and she's protected by double jeopardy. She's suspected of being the episode's killer, and not only is it not her (it's [[spoiler:her traumatized last victim]]), but [[spoiler:the PapaWolf of one of her victims goes to jail for beating her half to death]].
* KarmicDeath: A divorcing husband and wife are arguing over custody of his beloved pet dog. He gets an identical dog and tries to sneak it into her house. She catches him in the act and shoots him, but that's not the karmic part. [[spoiler: That would be when the new dog turns out to have been abused, goes berserk at the sound of the gunshot, and rips her throat out.]]
** A scammer that made a living selling the same exhausted mine once and again kills a man that knew too much and decides to disguise it as a mining accident. [[spoiler: He fails to leave before the fuse burns down and gets a splinter stuck on his brain.]]
* KilledOffForReal: [[spoiler:Warrick]], complete with PersonalEffectsReveal and MeaningfulFuneral. Holly Gibbs.
* KillerRabbit: Can we ever look at cornmeal the same way?
* TheKillerWasLeftHanded: Repeatedly, both with literal left-handedness and with problems with DNA in saliva.
* TheLabRat: Greg Sanders, whose nickname at TelevisionWithoutPity inspired this entry's title. [[PromotionToOpeningTitles He has, however, now become a CSI in his own right.]]
** Later seasons have made more use of the other lab rats - David Hodges (Trace), Archie Johnson (Audiovisual), Mandy (Fingerprints), and Wendy Simms (DNA). The show has given them two {{Lower Deck Episode}}s with the appropriately-entitled ''Lab Rats'' and the hilarious "You Kill Me".
** Unlike most Lab Rat characters on the CSI shows, [[BrilliantButLazy Hodges]] is quite content to remain indoors and ''hates'' going into the field.
* LampshadeHanging: After ten long years, they finally poke fun at their periodic explanations of how a test or piece of equipment works for the benefit of the audience, even though there's no good reason for, say, Sara to be telling this to Nick in the course of everyday work.
** Lampshades were also hung about being a forensics series in "I Like to Watch".
* LastNameBasis: Grissom (even by Sara, his girlfriend/wife), Hodges, Brass, Ecklie, [=McKeen=], occasionally Russell. Julie prefers 'Finn', short for her last name, Finlay.
* LawmanGoneBad: The team investigates a series of killings related to the murder of a mob boss many years before. It's mentioned that a patrol officer called in the car crash/body but mysteriously vanished along with the ill gotten gains and the possibility of this trope is discussed. [[spoiler: It turns out that the corpse that was thought to be the mob boss's was actually his; killed in order to serve as a decoy.]]
* LeftHanging: "Bad to the Bone". Six or seven subthreads, none of which were even close to being resolved.
** Pretty much every season finale since season 7 has been this way as well. They love their end of season cliffhangers.
* LethalKlutz: One episode features a guy like this. He accidentally kills his wife and somehow decides that the best thing to do was bury her in fresh cement at a construction site... where he gets stuck. It gets worse when they delve into his backstory. Some characters find his antics funny but Grissom is just disturbed.
* LifeOrLimbDecision:
** One episode begins with finding a dead woman who was missing a hand. They eventually find that she had bitten it off to escape from a psycho's basement.
** In "Consumed", it looks like a cannibalistic serial killer chewed through his own wrist in order to escape, leaving his hand handcuffed to the inside of a car. [[spoiler:It was actually staged to allow the killer to exaggerate his mystique]].
* LikeBrotherAndSister: Gil Grissom and Catherine Willows.
* LimitedAdvancementOpportunities: Avoided. Though the cast has remained more or less constant, their relative rank and internal structure have been adjusted, including Brass's handing over the department to Grissom (and going back to being a detective), the race between Warrick and Nick to achieve CSI 3, and Ecklie's breakup of the team into two different shifts, which prompted the promotion of Catherine Willows to supervisor, and made room in the ranks for Greg to go from lab tech to field agent. Later on, Nick gets promoted to Catherine's right-hand man and Ray has progressed rather rapidly from starting out at entry level.
** A particularly nice touch in Greg's case was Grissom making sure he really did want to make the lateral (and downward!) jump from Senior Lab Tech to extremely junior Field Investigator, reminding him that he'll be taking a substantial pay cut and that it will take quite a while to get back to his present level.
* LivingLieDetector: FBI Cybercrimes Agent Ryan. Unfortunately the criminals she hunts are anonymous internet users; fortunately it's very useful for startling people into doing what she wants (when a military pilot complains that he's not her chauffeur she points out that his "schedule" is to a tropical island with a woman who isn't his wife and-- "Welcome aboard").
* LockedRoomMystery: A more diluted form sometimes appears in a PoliceProcedural where the puzzle is eventually unraveled by an eccentric protagonist using more obvious clues and AppliedPhlebotinum.
* LongRunnerCastTurnover: Since the original premiered in 2000, its later seasons have seen the departure of three of its leads (Grissom, retired, and Catherine, new job, and Ray Langston (who replaced Grissom), forcibly resigned), two of its secondary leads (Sara, quit from PTSD but now CommutingOnABus, and Warrick, KilledOffForReal) and a number of its recurring supporting roles (Wendy, Sofia, and the very short tenure of Riley, meant to replace Sara). Most of the departures were of the "actor wanting to move on" variety, but contract disputes and in Warrick's case, personal problems, also factored.
* LongRunners: Thirteen seasons and counting.
* LowerDeckEpisode: "You Kill Me" and "Lab Rats", both featuring the lab techs.
* LukeIAmYourFather: Catherine's dad was a recurring casino owner who regretted not taking responsibility sooner, although the two were very close. This soured when Catherine found out that he had someone (probably a bunch of someones considering it was [[GangsterLand old Vegas]]) murdered; they managed to patch things up a little [[spoiler: before he was murdered]] and she now refers to him as "my dad".
[[/folder]]

[[folder:M-R]]
* MadDoctor: 'Doctor Jekyll'.
* TheMainCharactersDoEverything: Literally every possible police-related duty except handing out traffic tickets. It practically feels like the CSI team is an entire police department comprised of a dozen people.
** This show is pretty bad about this. In real life, [=CSIs=] simply go from crime scene to crime scene collecting evidence; they don't lab work. Right off the bat, a CSI's job is combined with a forensic scientist's job. They especially don't interview, interrogate and arrest people, even cities where the [=CSIs=] are police officers, they don't interview and interrogate people. Even Captain Jim Brass, the only actual main character with a badge, wouldn't be doing investigative work. The rank of Captain is a management rank, he'd spend most of his time at the station performing administrative duties.
** The combination of the CSI and forensic scientist jobs is due to CaliforniaDoubling. The real-life criminalist(s) who were involved in the development and consultation of the show in its early years mostly worked in Los Angeles, where most criminalists both collect evidence from crime scenes and do lab work.
** Somewhat justified as the showrunners say they simply do this to keep the main cast involved without tailspinning into LoadsAndLoadsOfCharacters. Fans of the show usually let this go by keeping the [[MST3KMantra mantra]] in mind.
* MamaBear: Catherine "Don't mess with Lindsey" Willows.
* ManipulativeBastard: The online "partner" of a troubled kid who shoots up the LVPD [[spoiler: who turns out to be a cop who had had enough of both her (allegedly) abusive cop husband (she sets it up so he's the first one shot) and her (allegedly) stalker-y "SWAT" lover (she used his computer to frame him as the "partner", plus he'd kill the kid)]]. Ironically they came into contact ''because'' the kid's mom wanted to help her son after his only friend was shot by cops and signed him up for (among other things) [[spoiler: an LVPD youth outreach program]].
* MarriedToTheJob: Both Sara and Grissom.
* MidlifeCrisisCar: Lampshaded.
* MistakenForCheating: Doc's wife, when a body turns up in her bed. It was really a set-up, with a wrong place, wrong time kind of feel.
* TheMobBossIsScarier: An episode had a hitman refuse a deal to name the man who hired him in exchange for not facing the death penalty, figuring he'd live longer on death row.
* MoodLighting: To the point of absurdity; autopsies and lab work are often performed in near total darkness!
* MonsterFangirl: Nate Haskell's "fiancée" in "Targets of Obsession".
* MonumentalTheft: In "Stealing Home", the CSI team investigate when an entire house is stolen.
* MsFanservice: Catherine and, briefly, Riley. Wendy might also count.
** Ronnie, Sara's swing shift partner, in "The Chick Chop Flick Shop."
* MulderMoment: "Fur And Loathing". The normally sexually-open Catherine is weirded out by the Furries while Grissom is typically intrigued.
* TheMurderAfter: Warrick and a stripper who is found dead in his car.
* MurderByMistake:
** In a particularly nasty example, a woman grief-stricken by news her teenaged daughter had been killed in a drunk-driving accident, slipped into the hospital and murdered the young woman who'd been driving the crashed vehicle. Turns out it was her own daughter whom she'd killed, as the two near-identical girls had both suffered disfiguring facial injuries, had swapped outfits and driving duties that evening, and her daughter had borrowed her friend's fake ID to buy booze.
** In "The Lost Reindeer", the murderer planned to kill the man hired to play Santa at a Christmas party. However, the Santa left early and one of the other guests put on the costume.
* MurderDotCom: Nick's plight in "Grave Danger" is broadcast live over the Internet.
* MurderSuicide: Generally played straight, though it was inverted in one episode where a stalker attempted suicide in his crush's house, resulting in three people dying.
* MyCard: The investigators will often give a witness their card and say "call me if you remember anything."
* MythArc:
** The "Miniature Killer".
** The Bathtub "Suicides".
** Dr. Jekyll.
** Nate Haskell.
* NauseaDissonance: In one episode, Catherine sends the rookie officer escorting her out because of this trope (she doesn't want vomit contaminating her crime-scene). The suspect turns out to have been hiding, and attacks her.
** This doubles as a CallBack when Warrick berates the officer for not clearing the scene because "[They] lost a CSI 2 years ago because of [that]." He's referring to the first episode, in which ''he'' was the one to leave another CSI alone at a crime scene.
* NecroCam: Done multiple times in every episode.
** The show is also notable for its gory body-dives, in which the camera flies around inside somebody's body (often tracing the path of a murder weapon), accompanied by all sorts of icky Foley noises. This is commonly [[FanNickname referred to]] as [[TooMuchInformation TMI]] Cam.
* NeedAHandOrAHandjob: Inverted when Catherine, while being evaluated by Grissom, complains about her lack of social life (and sex). "How can I help?" Grissom asks, and has to clarify that it's not THAT kind of help when Catherine raises her eyebrow at him.
** Another episode has Sara ask Grissom "Do you want to sleep with me?" Grissom has a {{Beat}} of WTF (this is before their RelationshipUpgrade, but went along with all the ShipTease they were having) before she reveals it to be a sarcastic offer, as Grissom had stated disbelief that she was having nightmares, and she says that he should be there to see her wake up screaming in the middle of the night in order to make him believe her.
* NeverSuicide: Subverted in one episode where an investor shoots himself at a party. It originally looks like a staged suicide since he's still holding the gun, which usually doesn't happen as the muscles relax after death.
** Another variation: The villain of an early story-arc staged identical suicides of men who were born on his father's birthday, the same date as and manner in which his father was murdered - up to and including a faked recorded suicide note. He did all this to prove his father's murder wasn't a suicide. This was eventually subverted as Millander, who it turns out was born on the same day as his father (and Grissom, incidentally), killed himself in the same way he had killed the other men.
** ''Inverted'' in another episode: a man is found in the woods with all the evidence initially pointing towards murder. It actually turns out to be a suicide designed to look like a murder so his wife would receive his life insurance money.
** Subverted yet again in another episode, when one man throws himself in front of a car. The entire episode runs like an ordinary investigation, the suicide letter being the final twist revealed only seconds before the episode ends.
*** Ironically, this ended up turning into a murder, as the driver that hit him had been drunk at the time and, rather than admit to hitting someone while intoxicated, hid the still-living man in his garage and tried to dispose of the body the next day.
** One double subversion, when a Sherlock Holmes impersonator is found shot to death. Like the above example, the episode runs as a murder investigation, until the team discovers the gun tied to an elastic in the chimney, revealing that when the victim shot himself and let go of the gun, the elastic snapped it back into the chimney. [[spoiler:Then we find out that the ''real'' murderer, in a reference to one of Holmes' later cases, had ''set the whole thing up to look like a suicide that had been set up to look like a murder'', as an appropriately Holmesian mystery. Yes, a murder, made to look like a suicide, made to look like a murder.]]
** "Trends With Benefits" starts out looking like the real-life suicide of Tyler Clementi (see Ripped From The Headlines), but it turns out [[spoiler: the victim's death was accidental]].
* NeverTrustATrailer: The 300th episode "Frame By Frame'' was promoted as featuring a return guest appearance by Marg Helgenberger, reprising her role as Catherine Willows. Some TV Guide entries even claimed that Catherine returns to assist the [=CSIs=] in a cold case. In actuality, Catherine only appears in flashbacks (newly shot, mind you), and the character never actually appears in the present time.
** The previous episode's trailer had Greg saying he's going to leave the CSI (after he had said in the last episode that, [[PutOnABus unlike]] [[TheBusCameBack Sara]], he'd never tire of the job); actually [[spoiler: he's afraid he's going to be forced to leave if it's proven his negligence put an innocent man in jail for a decade (it was actually a rookie cop who unwittingly contaminated the crime scene)]]
* NightSwimEqualsDeath: Too many episodes to list. It's usually signaled by finding the body floating in the swimming pool.
* NiceCharacterMeanActor: In-universe and for a ''TopChef''-esque reality TV star: [[spoiler: the show's producer was going out of her way to make him look like a nice underdog because he and another chef were her college buddies -- and then she found out they were the ones who raped her sister (I think). She [[BestServedCold turned him into four fancy dishes]] and poisoned his buddy with almonds (actual almonds (well, almond powder), not [[BitterAlmonds the bitter kind]]).]]
* NoBadgeNoProblem: ''CSI'' gets {{Flanderiz|ation}}ed into this in parodies but it's not as prevalent as it's made out to be. While the [=CSIs=] tend to do things that the police would be the ones to do in real life (like interviewing suspects or capturing them, though the latter tends to happen only when someone they plan to just speak to runs away), Grissom often reminds civilians he isn't a cop, and at one point was told to leave the scene by Brass when it became apparent that a suspect was still there.
** This said, it is quite common for them to enter a possible scene with weapons drawn... ahead of the actual cops.
* NoCelebritiesWereHarmed: Hilariously averted in volume 6 of IDW's tie-in comics. The story ends with them carting off [[spoiler:Creator/GregRucka]] for the attempted murder of Creator/JoeQuesada.
* NoSell: Agent Ryan doesn't flinch when a sadistic criminal has a gun to her face, nor does she bat an eye when he slashes her arm with a knife -- in fact ''she'' suggested he use it instead of the gun because it would be more "his thing" as a sadist (actually she was protecting the cops who were about to bust in and the slashing added years to his sentence).
* NonActorVehicle: Creator/JustinBieber guest-starred as [[BombThrowingAnarchist anarchist teen bomber]] Jason [=McCann=] in two episodes.
* NoodleIncident: DB and Finlay's past. ''Something'' caused them to become estranged for years. [[spoiler: Probably not an affair, seeing as DB's family wants them to get along.]] Turns out [[spoiler: Finlay went to extremes to prove a VIP was guilty and DB was forced to fire her despite believing in her.]]
* NotProven: If an episode wants a DownerEnding, this is usually the way it goes about.
* ObfuscatingDisability: "The Two Mrs. Grissoms".
* OccamsRazor: In a rather bizarre instance, Grissom brings this up in one episode to suggest that the killer was...the Nazi MadScientist EvilTwin of the man they thought was the killer. ''That'' was the "simplest explanation" he offered (he was right, of course, but still- hardly "simple").
* OffingTheOffspring: One woman was so devoted to her son that she [[spoiler: used her gangster boyfriend to murder her adult grandchildren and nearly her great-grandchild when she learned her granddaughter had evidence her son had molested them (his children, not the great-grandchild). Her excuse for being able to kill her own family so easily was the fact that she had given birth to and raised her son while the other three may as well have been strangers. For bonus horrible points the gangster thought the grandson was one of the robbers who raped his niece; it was actually the killer he hired]]. Sadly this was [[http://www.nbcnews.com/id/13098260/#.UpHIDOJBnI0 ripped from the headlines]] (and before you ask: [[OnlyInFlorida yup, Florida]]).
* OmniscientDatabase: Revolutionized this trope. They have demonstrated databases on blood, hair, rope, wire, shoe prints, tire treads, tire rubber compositions, and even clown makeup patterns. There was a LampshadeHanging in a sixth season episode, in which Hodges sarcastically suggested searching a database to discover the brand of a hot dog.
** To be fair, the clown makeup database belonged to a clown guild in Las Vegas, which is TruthInTelevision. Each professional clown is required to wear a unique make-up that is registered in the guild. Wearing another clown's make up us punishable.
** One episode featured a database that allows one to find where a picture in New York was taken by measuring the skyline in comparison to a reference height (while the technique is sound, there is no such software).
** An early Season Ten episode features a database on gangs, including cases related to each gang, their territory and their known members.
** In fact, it's when ''CSI'' avoids the trope that it can be jarring. A reoccurring scene is the local trace evidence guy naming a compound, and the CSI identifying the compound's common name, and its uses, including the more arcane (say, Jeweller grinder lubricant) on the top of their head. Said arcane use are always the key to cracking the case. This gets jarring because there ARE databases to identify the most common uses of chemicals.
* OneSteveLimit: [[AvertedTrope Averted]] with David Hodges and David Phillips.
* TheOnlyOne: The Crime Scene Investigators (and Brass) are the only law enforcement personnel who care about getting the criminals. The [=DAs=] only care about getting convictions, even if it is a wrongful one. Judges are at best unhelpful or helpless, at worst are corrupt and seek to hinder the [=CSIs=] in any way possible. Other cops just don't care. Parole boards are more focused on bureaucracy than on doing their job of making sure bad people stay in jail. ''Fire Departments'' are ridiculed for destroying evidence, and the never-seen day shift [=CSIs=] are a bunch of lazy incompetents.
** For the "other cops" part, subverted quite impressively by part-time ''Miami'' character Aaron Jessop, who apparently had the observational and mental skills to be a CSI himself. [[spoiler: Pity he tripped a booby trap and got blown up.]]
* OncePerEpisode: DB will mention his wife. Or call her. Or both.
* OnlyKnownByInitials: D.B. Russell.
* OpenHeartDentistry: In "Willows in the Wind", Doc Robbins (a pathologist) has performed impromptu field surgery on Catherine, cauterising a gunshot wound with a curling iron.
* OrificeInvasion / OrificeEvacuation / ChestBurster: Rats seem to like getting inside corpses in this show.
* OurGhostsAreDifferent: In one episode, four recently deceased people talk about how they died and what they'd been doing till then. One of the "ghosts" was an Iraq war veteran who just returned home only to be killed trying to stop a robbery. The other three remark that it must have been the saddest day of his life, but the 'vet said for him it was the happiest, because [[TearJerker he got to see his newborn son for the first time.]]
* OutrankingYourJob: Brass spends a surprising amount of time kicking down doors for a police captain. Averted by Ecklie, who rarely investigates a crime scene himself, as befitting his supervisory role.
* PapaWolf: The occasional suspect, especially in the case of an AssholeVictim.
** Grissom also gave Catherine's abusive ex-husband an OhCrap moment when said ex tried to bully Catherine.
** In fact, Grissom tends to go PapaWolf whenever his team are at risk of harm, for all he usually comes across as emotionally distant.
** D.B. now. Do not mess with his family.
** Ecklie has his moments of this when it comes to Morgan. He's not pleased when he finds out that Morgan testified on Hodges' behalf at a hearing for his possibly-a-Green-Card-scam engagement, and he punches a guy in the face when he won't admit to knowing where a kidnapped Morgan is. As he doesn't really have quite as much of an opportunity to go out and investigate things as the others when Morgan ends up in danger (as he's the Undersheriff/Sheriff), he doesn't get as much PapaWolf behavior as the other examples here, but it's still ''very'' obvious that you do ''not'' want to be around him and be someone who's hurt her.
** Some of the fathers involved in the cases qualify.
* PaperThinDisguise: By the DiabolicalMastermind in "Living Legend". It's not so much that they don't see through his disguises (after all, he's been missing for 30 years), it's that no one notices that the disguises ''all look like one another''.
* ParanormalEpisode:
** Had an episode with a psychic helping the [=CSIs=]. He died before we could find out if he was a fraud, though all his predictions did come true.
** "Toe Tags", which had the stories told from the corpses' perspective, like they were ghosts.
* ThePerfectCrime: In "Working Stiffs", a lowly office drone makes a seemingly perfect get rich quick scheme. [[spoiler: He manages to get the unbreachable safe open, but is crushed against the wall by a piece of it that comes flying at him. Upon seeing he actually succeeded in doing the impossible, his last words are "I knew it would work..."]]
** Played straight whenever they don't get the perp, though special mention goes to "Alter Boys" ([[spoiler: the team knows for sure that the actual killer is not the man arrested but his EvilTwin, yet every bit of evidence points to the former]]), an ep with one of the most remarkable [[DownerEnding Downer Endings]] in the show.
** Before both of these was "Organ Grinder", in which the perps were a tag-team of {{Black Widow}}s who would go from state to state, one of them marrying wealthy men for their money and the other poisoning the husband, with the roles flip-flopping every other kill. They would then meticulously destroy all evidence so that the only thing investigators would have on them would be their own testimony... and then each flip on the other, forcing the authorities to let them go. They end up being the first perps on the show to [[KarmaHoudini get away completely scot-free]] (not counting Millander, who is brought down later on). In an interview, the episode's writer said she realized this was a huge {{Anticlimax}}, and if she had the chance to write it again she would've had one kill the other and go down for it.
* PerpWalk: Almost at least OnceAnEpisode.
* PetTheDog: A posthumous one for [[SerialKiller Millander]], as his son has only happy memories of his father, especially of his father's (though he didn't know it at the time) special effects shop.
* PluckyComicRelief: Greg Sanders is an excellent example of this trope.
** Not so much anymore, now that he's had several serious character arcs (not to mention becoming one of the most experienced [=CSIs=] on the team). The role has been taken over by Hodges and the supporting [[TheLabRat Lab Rats]].
* PoliceAreUseless: A major wallbanger happens in Season 11's "Cello and Goodbye". Ray catches up to Nate Haskell at a carnival, both men have guns drawn. Haskell is raving about how Ray's ex-wife is still alive, wielding his gun all over, yelling at the top of his lungs, and just seven feet away. Cops catch up to Ray and... [[ItMakesSenseInContext arrest Ray.]] They [[PlotInducedStupidity somehow]] miss the [[UnusuallyUninterestingSight screaming madman on a nearby platform with a big gun.]]
* PoorlyDisguisedPilot: ''CSI'' did this to launch ''Series/CSIMiami'', which in turn launched ''[[Series/CSINewYork CSI NY]]''.
** And the episode "Hollywood Brass" certainly feels like a PDP. Were they thinking about a Jim Brass spin-off set in LA?
** It seemed possible also with the episode "The Thing About Heroes" of ''CSI NY'', which introduced at least one major character from the Chicago police department, but no spinoff was launched.
** Rumours circulated for a while about a possible CSI London (although for accuracy, it should be SOCO London, as the real-life CSI equivalents of the British Police are called Scene Of (the) Crime Officers[[note]] The NYPD relies on ''CSU''--Crime Scene Unit''[[/note]]) such that, when Mac Taylor of {{CSI NY}} visited London, there was an expectant hush among some viewers... which dissipated almost immediately, since London was just a stock-footage pretty backdrop for a mystery phone call, part of a very definitely American story arc.
** The "Cybercrimes" episode ''definitely'' felt like a pilot... and it was ordered to series as ''CSI: Cyber''.
* TheProfessor: Ray.
* PutOnABus: Inevitably for such a long-running series, this has happened several times.
** Sara and Grissom, presumed retired for good, although Grissom did have a cameo in Season 11's "The Two Mrs.Grissoms". Sara returned for a few episodes starting in Season 10, and began CommutingOnABus starting in Season 11.
** Catherine as of Season 12.
** Wendy (Liz Vassey) got on the bus in Season 11.
** Sofia and Riley also make quick exits even after getting promoted to the titles.
* QuipToBlack: The ''CSI'' examples are famous.
** Grissom started the trend, but, to be fair, it was ''Series/CSIMiami'' that took it to a (much cheesier) new level.
** Averted in one early episode where Grissom makes a quip, the musical cue for the fade happens, but is suddenly interrupted by Grissom's cell phone, informing him of another case to handle. At that case's location, he makes another quip with the cue, and his phone rings ''again''. At this third crime scene, Grissom doesn't even bother making a quip, and the show fades into the theme.
* RealMenGetShot: Brass and his "injury date" tattoos.
* TheReasonYouSuckSpeech: All three series have their fair share of these, but Catherine is the subject of a brutal one from Leo Finley at the end of "A Thousand Days on Earth". Even though he's innocent of murder, Leo's fiance, Norah, now knows he's a sex offender because Catherine dug up his past during her investigation. He explains to Catherine that Norah kicked him out of his own home and got a restraining order, in addition to telling all their neighbors as well as his boss, resulting in him losing his job, and it's all Catherine's fault. You can feel Leo's pain as he calls Catherine a "blonde Nazi bitch" and screams at her for not caring about ruining his life before telling her in a chillingly calm tone that he's thinking about killing himself and that if he does, that'll be her fault too.
* RecklessGunUsage: Nick Stokes investigates how a woman got shot with no evidence of a shooter anywhere near. The answer is that [[spoiler:there was an idiot who had a gun and made a shooting range in the backyard, in the suburbs within city limits, a big-time city ordinance no-no, and a stray bullet went into the air and [[IJustShotMarvinInTheFace struck the woman on the decline]]]]. When they arrest him, he protests it was an accident and Stokes contemptuously responds [[spoiler:"Well, that's why it's illegal to shoot guns within city limits, genius!"]]
* RasputinianDeath: The episode "Ending Happy" - played for comedy!
* RealSongThemeTune: "Who Are You", by Music/TheWho.
* RedemptionEqualsDeath: Keppler killed an innocent man on the word of a corrupt cop. Guess what happens in the episode that outs the secret?
* RegularlyScheduledEvil: Serial-killing dentist Doctor Dave (played with chilling effect by the great Ned Beatty) started killing when he was in his late teens, and only got "the urge" every ten years or so. He doesn't get caught until he's in his seventies. The length of time between murders is one reason it took so long for the police to catch him.
* TheReliableOne: Back in the days before he was promoted to the main cast, DNA specialist Greg Sanders was this. Once he became a featured player, this position was taken up by David Hodges, much to the surprise of everyone.
* RevolvingDoorCasting: Seems to slowly be heading towards this with the original cast gradually leaving the show and replacements being brought in over time. [[note]] As of Season 13, the remaining original cast members include George Eads (Nick), Jorja Fox (Sara, who has been CommutingOnABus for several seasons), Eric Szmanda (Greg), Robert David Hall (Doc Robbins), and Paul Guilfoyle (Brass).[[/note]]
* RippedFromTheHeadlines:
** "Unfriendly Skies", inspired by the [[http://en.wikipedia.org/wiki/Jonathan_Burton Jonathan Burton]] case and aired only months after the incident.
** "Anatomy of a Lye", based on the [[http://en.wikipedia.org/wiki/Gregory_Biggs Gregory Biggs]] case.
** "After the Show", an almost word for word retelling of the [[http://articles.latimes.com/1996-12-17/news/mn-9958_1_linda-sobek Linda Sobek]] murder, and specially notable for having been co-written by Elizabeth Devine, a former CSI involved in the original case who is now a consultant to the show.
** "Trends With Benefits" is based on the [[http://en.wikipedia.org/wiki/Suicide_of_Tyler_Clementi suicide of Tyler Clementi]] who was outed by his roommate with his webcam, with a twist: [[spoiler: The gay college student's death was an accident, him being gay wasn't an issue, and ''he'' was the one who was using hidden cameras (he wanted to be the next Perez Hilton), in this case to expose his professor raping a student.]]
** "Burked", based on the Binion murder case. [[spoiler: While the key story elements are there, the identities of the killers are different.]]
* RuleAbidingRebel: Investigating a death during a high-stakes poker game, the heroes discover that the waitress put eyedrops in the victim's drink as payback for him being a lousy tipper. She'd meant to give him diarrhea and force him to leave the game early, but he died before they kicked in.
* RunForTheBorder
* RunningGag: Mentioned by name by Hodges in "You Kill Me".
[[/folder]]

[[folder:S-Z]]
* SacrificialLamb: The series began with a NaiveNewcomer character who basically served to introduce the various members of the show's cast. With that out of the way, she caught two in the back of the head, turning into the second victim and confirming her status as the NewMeat.
* SarcasmFailure: When Grissom doesn't do the QuipToBlack.
* ScaryBlackMan: Several of these have been suspects over the years.
** An amusing subversion came from a black teenage gangbanger and SmugSnake, who tried to use this trope to intimidate Warrick. Warrick, of course, wasn't the least bit impressed.
* ScienceHero: Grissom and, later, Ray.
** Most of the [=CSIs=], really. Rather than bringing in criminals, they catch them using various forms of forensic analysis (blood spatter, facial reconstruction, DNA matching, etc).
* TheSecretOfLongPorkPies: In "Appendicitement", the owner of a BBQ restuarant was killed by his wife and the cook, who then disposed of the body by cooking it up and serving it to the customers. The flashback implies it was very popular.
* SeekerArchetype: Grissom again.
* SerialKiller: The Miniature Killer, Doctor Jekyll, the Blue Paint Killer.
** Season 1 alone had three: Paul Milander, the I-15 Killer and the Strip Strangler.
* SerialKillingsSpecificTarget:
** In one episode, a comedian dies from drinking a poisoned bottle of water. Then a kid dies from drinking the same brand. [[spoiler: The first victim was the target; the killer (a rival comedian who hated his style) says he blames the [=CSIs=] for not finding the poisoned bottle in time as he's arrested after confessing out of remorse.]]
** [[BigBad Doctor Jekyll]], when finally caught after a season-long killing spree, was in the process of murdering the true object of his rage- [[spoiler: his own father.]] Played with in that every victim was connected to the main target, friends and acquaintances that they admired, so every murder was designed to make them suffer before they died, as well as giving Jekyll a chance to take out his frustrations on somebody.
* SeriesContinuityError: Sara says in one ep she has a brother, then in season 12, she says she was an only child.
** Sort of with the original bios on the CBS website. Catherine was said to have been born in Bozeman, Montana (likely recycled to ''{{CSI NY}}''[='=]s Lindsay) and Grissom's father was said to have been involved in smuggling. The first guidebook, covering the first three seasons, has this information as well.
* SeriousBusiness: Among others, the FurryFandom, Scrabble, eating contests, and vampires vs. werewolves {{LARP}}ing.
** Robot Rumble!
* SexIsEvil: One of the more frequent knocks on ''CSI'' is that this is pretty much how it treats any sex practices (regardless of consent) outside of hetero and committed.
** This is a common problem with any CrimeAndPunishmentSeries, really, as the only time the characters usually encounter alternative lifestyles is when there's a grisly murder involved.
--->[[RuleThirtyFour Rule 34a]]: There's also a ''CSI'' episode about it - no exceptions.
** ''CSI'' tends to be a bit schizophrenic about this, really. While they tend to portray "perverts" of various types as being twisted in various way aside from their sexual appetites, those that weren't involved in the crime of the week, and even some who were, are ultimately portrayed sympathetically for the most part. The best example is {{Recurrer}} Lady Heather, a dominatrix who is a tragic and sympathetic character. Admittedly, most of the tragic part is in some way due to her lifestyle, but it is ultimately left up to the viewer to decide whether this is due to her own "sins," or other people's (including her own daughter) reaction to them.
** Humorously, ex-stripper Catherine seems to be the most squicked out by alternative sexual practices. Grissom, of course, finds it all very fascinating.
** Toyed with in an early episode where Nick sleeps with a woman who is found dead the next morning. As the last person to see her alive, he is automatically the prime suspect in the investigation. Turns out, she was a prostitute who was going to go solo, and her former pimp killed her after Nick left her house.
* ShamefulSourceOfKnowledge: {{Inverted}} on an episode which is set over the course of a year. A junkie who Nick helps out at the beginning (and slowly sorts himself out over the course of the episode) recognises the smell of some drugs [[spoiler: the murderer poisoned the victim with]]. However, he isn't willing to reveal what he knows until ''after'' he's gone clean, since he didn't think he'd be believed.
* ShipSinking: [[spoiler: Turns out Grissom and Sara's very, very, ''very'' long-distance relationship was too hard. Also Sara's potential romance with a hook-up: not only was he murdered by the stalker from the diner massacre episode, the stalker taunts her with the fact he had to pay him to see her again.]]
* ShipTease: Grissom and Catherine playfully flirt with each other and it never goes anywhere. To wit:
-->'''Catherine to Grissom:''' ''(while helping the latter put on a tie)'' You need a woman.
** Grissom, when Catherine returns from Miami in which she helped investigate a case there, "I missed your tush".
** The "[[NeedAHandOrAHandjob How can I help?]]" scene (see above for details).
** There have also been hints towards possible Nick and Sara - WordOfGod states that Sara's phonecall at the end of "You've Got Male" was originally intended to be to Nick, and they have had moments of reciprocated flirting. Likewise, Catherine and Warrick, to the point where Catherine is upset to learn of Warrick's marriage and even outright comments on losing the dream.
** Grissom and Heather could also fall under this as it is never outright confirmed that anything happened between them. Heavily implied, yes, but always in a way that, taking Grissom as being Grissom, could have a perfectly innocent explanation.
** There were hints here and there for Greg and Sara as well, especially during her time mentoring him in the fifth season. A notable example comes from the episode "4x4":
--->'''Greg:''' Sara, I just want you to know that when we were in the shower, I didn't see anything.
--->'''Sara:''' Really? Gosh, I saw ''everything''.
** Grissom and Sara themselves in the first season.
--->'''Sara:''' Do you want to sleep with me?
--->'''Gil:''' ...Did you just say what I think you said?
*** Although that was a RuleOfDrama moment, as Sara was setting him up for her rationale for taking their current case personally: that if they slept together, then he would know how serious her nightmares were regarding the victim.
* ShipperOnDeck: DB seems to ship Morgan/Greg, seeing as how he's called Greg her boyfriend on at least one occasion.
* ShootTheShaggyDog: "[[spoiler: Fracked]]", essentially. Just when the team think they've figured out what's going on, Ecklie [[ShockingSwerve randomly forces them to close the investigation]] [[DiabolusExMachina for no real reason]]. Particularly infuriating because the team ''have'' been allowed to proceed with investigations in which they had much less evidence than this one.
* ShotToTheHeart: Doc Robbins does this in one episode, where a guy revives on his table.
* ShoutOut: Hodges and Langston do a very-thinly-disguised ''Series/MythBusters''-style experiment, complete with Plexiglas shield. All they needed was the "3, 2, 1!" part. There is also the experiment conducted by Nick and company with a ballistics gel dummy.
** In an earlier episode, Savage and Hyneman make a cameo observing such an experiment conducted by Nick, involving a taser and the flammability of pepper spray.
*** To make it go full circle, Mythbusters in turn tested the experiment as part of their show. For the results, you'll have to see the episode in question.
** In another episode, a missing woman is found with a SerialKiller at a place called [[VideoGame/HalfLife Black Mesa]].
** Hodges' cat is called [[Series/StarTrekTheOriginalSeries Kobayashi Maru]].
** [[Series/BattlestarGalacticaReimagined Boomer and her creator]] look on in horror as a Franchise/StarTrek expy is given the DarkerAndEdgier treatment.
** The 2009 season opens with an extended BulletTime extravaganza, complete with [[Film/TheMatrix Morpheus kicking an "Agent" through a window]].
** "[[Series/TrueBlood Blood]] [[Literature/{{Twilight}} Moon]]"'s ColdOpening looks and sounds a lot like ''Series/TrueBlood'''s opening titles.
** "Fracking" also happens to be detective [[Series/BattlestarGalacticaReimagined Starbuck's]] second episode and has a direct reference:
--->'''Reporter''': Do you know what "fracking" is? (it's [[http://gaslandthemovie.com/ explained here]], which appears to be the episode's inspiration)\\
'''Langston''': Sounds like a sci-fi expletive.
*** Also includes an ''Erin Brockovich'' reference to Catherine (she's not [[JuliaRoberts Erin Brockovich]], but she was a client).
** Several Creator/QuentinTarantino motifs are used in the Season 5 finale he directed and co-wrote: Warrick and Nick have a SeinfeldianConversation before going to work, Grissom has a rare piece of Lone Ranger memorabilia, there's a DeathAsComedy moment, [[KillBill a character gets buried alive for a good chunk of time, and Grissom even gets to say, "On any other day, you'd be 100% right, but today, you're 100% wrong."]]
* TheShowGoesHollywood: "Hollywood Brass" and "Two and a Half Deaths".
* ShownTheirWork: More often than you think; it's the editing that turns it into HollywoodScience. All the equipment in the CSI lab are fully operational. There's also the episode involving a not!Star Trek convention, which is filled with references, including the Picard Maneuver. The shirt-tugging one.
* ShowWithinAShow: 48 Hour Mystery, a TrueCrime show, having episodes such as "I-15 Killer" and "The Firefighter Imposter", referencing "true" crimes shown in previous episodes of CSI.
* ShutUpHannibal: Langston had several moments like this with Nate Haskell.
* SickEpisode: ''Grissom's Divine Comedy''
* SideBet: In one episode, Greg Sanders's replacement eventually cracks from the pressure to be just like Greg and quits. Nick forks over a bill to Warrick. (Who really [[BrokenAesop shouldn't have been participating]]...)
** There's also been a whole episode with a RunningGag about Nick and Warrick having a bet on what happened to the Vic of the Week. Either Warrick can engage in "fun" bets with a buddy without a problem, or, considering this was one of the earlier seasons, the writers were letting their sometimes schizophrenic approach to characterisation show.
** Another episode sees Catherine and Grissom make a bet over whether two murder victims' deaths were related or not (they were long lost twins). In the end it turns out they were both right, and Catherine rips a bill apart, handing half of it to Gil. This comes after a very heavy conversation, lending to a tension breaker when Grissom reminds her that doing so is a federal offense.
* SinisterShiv: One episode featured a shanking in a juvenile detention facility with a shiv made from a razorblade melted into the handle of a toothbrush.
* SkinnyDipping: "Fracked" opens with three teenagers skinny dipping in hot spring. They discover a dead body floating in it.
* SlasherSmile: [[http://static.tvtropes.org/pmwiki/pub/images/fuelriffic_Rylan_Gauss_2_1515.JPG Rylan Gauss]] in "418 / 427".
* SleepingWithTheBoss: Grissom and Sara, although much has changed since he left and she left, then returned.
* SnuffFilm: "Snuff".
* StabTheSalad: Used in TheTeaser of "Dead of the Class". David takes a knife from the block in his kitchen and slowly and menacingly walks into the bedroom to where his very pregnant wife is lying down. He asks her "Why must you force me to do this?" in a suitably menacing tone ... then proceeds to use the knife to cut the tags off a new dress shirt. They were talking about him having to go to his high school reunion without her because she's too tired to stand.
* StageMagician: The Amazing Zephyr from "Abra-cadaver".
* StrayShotsStrikeNothing: Averted. In one episode a man fired a handgun into the air and accidentally killed a woman who lived miles away. Sadly, it was probably inspired by one of a number of cases in RealLife where people carelessly firing off guns in celebration have killed innocent bystanders.
* {{Streetwalker}}: The first season has Nick falling for the hooker, Kristy Hopkins, who is indeed killed by her pimp. According to her pimp she lied about wanting to get out of it.
** Something similar happens to Warrick in the eighth season, where he was framed for her murder.
** Catherine Willows could be considered this, as she is a former stripper. She hasn't been killed, but constantly faces people and places from her dubious past.
** Likewise, Grissom's one-time potential love interest Lady Heather could be considered this as she was an intelligent but intense woman who ran an S&M club. She, however, was not the delicate flower in need of nurturing but more of a velvet glove and iron fist in one.
* SpannerInTheWorks: Several criminals are apprehended when other people unwittingly discover their victims' bodies or provide evidence that allow the [=CSIs=] to catch them. Children who get chemical burns from the lye used to try and dissolve a buried corpse, panicking teenage girls who steal a car containing a severed head before the killer has a chance to bury it (see DeadMansChest above), one of the same girls slapping her hand on a murderer's car and leaving a handprint that proves the killer was there at the time of the murder, or a HeroicBystander catching a Peeping Tom who also turns out to be a serial rapist, have all given the [=CSIs=] invaluable help over the years.
* TheSpock: Grissom.
* SpontaneousHumanCombustion: One episode has a subplot dedicated to SHC. After finding a charred corpse with all the hallmarks of RealLife SHC cases, the characters conducted an experiment; they wrapped a pig's corpse in the woman's clothing, put the corpse on an identical lounger to the victim, doused the pig with liquor, and lit it up, thereby replicating the scene that they found. Grissom, who already knew about [[http://en.wikipedia.org/wiki/Wick_effect the Wick Effect]], congratulated the experimenters on a successful experiment, and then told them that this was coming out of their paychecks since it was unnecessary.
* SubcultureOfTheWeek: In many episodes.
* SuicideIsShameful: In the episode "Who Shot Sherlock?", Greg cites the possibility that a relative of the deceased covered up a suicide as a possible explanation for contradictory evidence at the crime scene. In an odd twist [[spoiler:it turns out to be a murder staged to look like a suicide which was staged to look like a murder because of this trope.]]
* SuperDeformed: The ''CSI: Crime City'' Facebook Game, where you play a new member to the Las Vegas CSI lab, and must not just search for evidence, but also process it to apprehend the killer of each case.
* SuspiciouslySimilarSubstitute: Dr. Raymond Langston (played by Laurence Fishburne) replaces Grissom in Season 9, though not in terms of position. Riley takes Sara's place.
** Ray Zig Zags the trope. Being the new guy, he's not the TeamDad that Grissom was, but does take over Grissom's role of the older, sheltered, quiet, intellectual guy.
** DB Russell plays it a bit straighter. He's quirky like Grissom, has the TeamDad element about him, and has some of the sense of humor at times.
* SwallowTheKey: In "Abra-Cadaver," the killer, a StageMagician who was perfectly willing to kill his family members for the sake of illusions, does this at the end (although Grissom [[GenreSavvy did think to check his mouth).]]
* SympatheticMurderer: Played absolutely straight in one episode with a guy who is responsible, by complete and total accident, for the death of his grandmother, wife, and next door neighbor, and winds up buried up to his waist in cement for it. The whole thing reads like an extended version of ''TheFarSide'', complete with the wife wearing cats-eye glasses.
** Then there was the guy from "Lying Down With Dogs" who [[spoiler: was an FBI agent undercover in a dogfighting ring who could never get enough evidence to prove what was really going on, and was thus forced to watch innocent animals being abused in every way imaginable without being able to do anything, eventually snapping and killing the head of the ring by subjecting her to every torture she put the dogs through.]]
** Quite possibly [[spoiler: Ray, who seems to have killed Nate Haskell by dropping him from the second story of his (Nate's) house after tying him up. Justified in that Nate is a serial killer who murdered Ray's ex-wife's husband and tortured her for days. Either way Ray's not returning next season.]]
* TakeAThirdOption: In the first season, Warrick and Catherine catch a teenage boy who accidentally ran over a little girl. Warrick gives the remorseful kid his number, and tells him to call if he runs into any problems in juvie. In the next season, the kid witnesses a teenage gangbanger murdering his rival. The DA wants the kid to testify, and threatens to extend his sentence if he refuses. On the other hand, the kid knows if he does that the other inmates will kill him. Instead, he calls Warrick for help. Warrick's investigation finds enough evidence to convict the gangbanger without the kid needing to testify.
* TakeFive
* TeamMom: Catherine for a long time...now Sara's kind of getting into it.
* TelevisionGeography: The frequent presence of lush greenery and vegetation, and moderately frequent rain, in desert Las Vegas on ''CSI'' ([[CaliforniaDoubling filming in LA]], also a desert but heavily watered) is often a source of amused derision by show fans. Also, Geoff Duncan has written two articles on the geographical inaccuracy of two outside jobs, one in [[http://www.teevee.org/archive/weblog/2003/11/10/102730.html "Jackpot"]] and another in [[http://www.teevee.org/archive/weblog/2004/09/24/095909.html the 2004 season premiere]].
* ThemedAliases: In "Living Legend", the killer uses aliases that the names of movie serial killers: Michael Myers, Pamela Voorhess and F. Krueger.
* ThereAreNoCoincidences: Gil Grissom repeatedly says that he does not believe in coincidences. He even quoted ''Film/{{Goldfinger}}'' at one point, saying "Once is happenstance. Twice is coincidence. Three times is enemy's action." However, in the episode "Chaos Theory", Grissom is forced, at the end of the episode's investigation, to accept that the death and disappearance of college student Paige Rycoff was the result of a series of unfortunate random events that, when taken in sequence, were only connected because, together, they directly led to the girl dying in a tragic accident that merely ''appeared'' at first blush, to be murder.
* ThisBearWasFramed: In one episode, a woman (who was eating human organs to fight off a rare disease) used dogs to attack her victims, so that the deaths at first simply looked like dog attacks.
* TimeDelayedDeath: Several examples:
** A man who was punched in the back of the head in a bar fight, who later died of a brain hemorrhage in the bath.
** A boy who was [[spoiler:stabbed trying to prevent his little brother from murdering their mother's boyfriend]] tries to walk home, but collapses and dies... right under the tires of a cab. The cabbie then [[spoiler:gets [[VigilanteExecution beaten to death by a mob]] who thinks he ran the boy down and was about to drive off, when he was actually going for his radio]].
** This was the killer, Dr. Jekyll's pattern, he would knock them out and perform surgery on them that would sabotage their body from the inside, thus causing them to die weeks after the incident without them knowing why.
** A football coach is savagely beaten about the head while he sleeps; the next morning he wakes up, brushes his teeth, has breakfast and gets the paper while bleeding profusely from his head and mouth. The ME concludes that parts of his brain was just intact enough to "zombie-walk" him through his morning rituals.
** A miner gets a long splinter stuck on the top of his head and manages to drive from a mine in the mountains to a casino parking before he collapses and dies in front of a police officer. The cop is understandably confused.
* TokenMinority: Warrick Brown until 2008. This role was then played by Dr Raymond Langston (Lawrence Fishburne). Now, there isn't one (after 2011).
* TonightSomeoneDies
* TrueLoveIsBoring: Grissom and Sidle. After years of UST, their separation just comes somewhat out of left field.
* TrustMeImAnX: From "The Theory of Everything":
--> '''Hodges:''' Trust me, I'm an expert.
** And then [[CrowningMomentOfAwesome Wendy kicks his ass]].
** [[BelligerentSexualTension Wendy kicks his ass frequently]]. The first time he doesn't completely screw up in a [[LowerDeckEpisode Lab Rat Episode]] is when he finally gets a kiss.
* TwoLinesNoWaiting: Nearly every single episode for most of the run. Occasionally the characters will find out halfway through the episode that the [[HalfwayPlotSwitch crimes they are investigating are tied together.]] Some episodes pull this off better than others.
** There have been less of them recently for budget reasons - you essentially have to hire twice the guest cast.
* UndersideRide: In "XX", a woman tries to escape from a prison in this way and suffers LudicrousGibs from getting caught in the moving parts. [[spoiler:Subverted when we find out that she was already dead - the killer was getting rid of the body]].
* UnfortunateName: Diebenkorn. Not a punny or risque one, but still one that he'd probably like to forget.
* UselessSecurityCamera: Usually, whenever crimes take place in corner shops, the owner will imply that it's not a real camera (or that it doesn't work) without even having to say it.
* VengefulVendingMachine: Brass once helped a witness's mother get a soda from the lab's vending machine, which had taken her for $2. He rattled its controls in the right way to get it to cough up the stuck can for her.
* TheVerse: In addition to its [[Series/CSIMiami three]] [[Series/CSINewYork spinoff]] [[Series/CSICyber shows]], the show has also shares a universe and crossed over with fellow CBS procedurals Series/WithoutATrace and Series/ColdCase.
* VignetteEpisode: "Toe Tags".
* VillainEpisode: "Killer" and "Working Stiffs".
* WeAreEverywhere
* WelcomeEpisode: Subverted in a major way by having a WelcomeEpisode premiere which ended with NaiveNewcomer Holly Gribbs [[SacrificialLion getting shot dead]]. This is then played straight when Sara Sidle is brought in to replace her/act as an independent investigator.
* WellDoneSonGuy: Presumably [[spoiler: Dr. Jekyll's dad. In an interesting twist the dad wanted his son to have a creative career (chef) while the son wanted a more disciplined one (surgeon).]]
* WellIntentionedExtremist: [[spoiler: The "neighborhood watch" guy, who can't move due to the economy and has to see an internet porn business and a crackhouse open up on his street.]]
* WeirdnessCensor: One episode that dealt with a murder in a crowded theater referenced "[[http://www.theinvisiblegorilla.com/gorilla_experiment.html The Invisible Gorilla]]", one of the most well-known experiments in the history of modern psychology, as an explanation for why a group of bystanders just stood there and ignored a horrible crime happening in their presence: the audience was concentrating so hard on the show that they missed the murder happening right in front of them.
** "The Invisible Gorilla" operates thusly: a test group watches a video that featured six people, three in white shirts, three in black shirts, passing a basketball back and forth. The test group was instructed to carefully count the number of passes made from one person to another. Afterward, the test group was asked, "Did you notice the gorilla?" Turns out that at one point in the video, a man in a gorilla costume walks into the middle of the basketball players, thumps its chest a few times, then walks off-stage. In total, the gorilla is onscreen for nearly nine seconds, and no one ever spots (even those people who go into the experiment knowing there is going to be a gorilla tend to not spot it at all).
* WhipItGood: Lady Heather.
* WorkingTheSameCase: Frequently.
* WorstAid: Usually averted, but in an episode where Nick finds a missing teen who's sprawled unconscious in a ditch after being struck by a car and knocked down a hill, he ''turns her head'' as he's checking her injuries. As it happens, when next she's seen on-screen she's mostly paralyzed, in traction and a neck brace...
* WrongGeneticSex: In one episode, a DNA sample with female chromosomes turned out to belong to a male character. He was a post-operation trans man and it wasn't known that he had been born female-bodied.
* YouNeedToGetLaid: When Nick jokingly tells his nerdy LabRat coworkers they need to get a girlfriend, it backfires both times. David reminds Nick he's ''engaged'', and Archie just scoffs, "You first!"
* YourOtherLeft: "Alter Boys"
* YouthIsWastedOnTheDumb
[[/folder]]

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!!The CSI video games provide examples of (in addition to many listed above)

* ArtEvolution: Just look at the graphics for ''Fatal Conspiracy'', and then look back at the very first CSI game. Yeah...
* AWinnerIsYou: After you beat a case with 100% completion, you usually just get Grissom telling you, that doesn't happen often, and that he's very impressed. If you don't get 100%, he just berates you and tells you to try better next time. To be fair though, it is [[FridgeBrilliance in character]] for Grissom to give you such a bare minimum evaluation. In the games made after William Petersen's departure Catherine gives you a more glowing evaluation, making you feel like you really accomplished something. However, she pretty much says the same thing regardless if you get 100% or not.
* BackTracking: The amount of times you have to keep going back to a crime scene, or a suspect's place (just to gather more evidence, or get more information) is a little ridiculous and unrealistic, especially when compared to the TV show. The game designers sort of lampshade it though sometimes by having the suspects get ''really'' agitated with you everytime you come back to get more info, or look for more evidence.
* BrickJoke: Each CSI game comes with 5 cases. For every 5th case, a suspect from an earlier case who was later deemed innocent shows back up again, and usually turns out to be heavily involved with the current case, or is the actual murderer.
* CharacterTics: Some suspects have these, and they become essential to the case later. One female suspect in one game keeps fidgeting with her fingernails during questioning. It's later revealed because she broke a fake nail, and the broken piece turns up on the victim's dead body.
* CliffHanger / DownerEnding: The ending to ''Fatal Conspiracy''.
* EarlyInstallmentWeirdness: The very first CSI game had poor graphics, and the characters just barely resemble the actors from the TV show. The cases were much shorter, and in the first two games, Greg did all DNA, print, and chemical matches for you.
* FaceHeelTurn: Practically a ''fleet'' of police officers and undercover agents in the game ''Fatal Conspiracy''.

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