CSI: Crime Scene Investigation

""Concentrate on what cannot lie -- the evidence.""

- Gil Grissom

CSI: Crime Scene Investigation (sometimes unofficially referred to as CSI: Las Vegas when comparing or differentiating the shows in the franchise) 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 ten seasons to make the characters a little more rounded and include more of their personal lives and histories in the storylines. 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.

Influenced a great many subsequent programs; most directly, it inspired its producer, Jerry Bruckheimer, to try and replicate this success with Without a Trace and Cold Case (both in the same verse). It also followed in Law and Order's 'franchise' footsteps, with CSI: Miami (Yeeeeeeeaaaahh!) and CSI: NY. As of the 2008-2009 season, there are over 600 total episodes of CSI, CSI: Miami (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 Silent Witness, while Waking the Dead aired its pilot a few weeks earlier.

Gil Grissom's frequent one-liners right before the opening credits or an ad break are a well known example of a Quip to Black, although Horatio Caine's versions are perhaps the best known - mostly due to the heaping layer of cheese added to them. Pretty much established the Necro Cam, 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 Applied Phlebotinum has caused some to suspect that it's not actually set in the present day, but, rather, Twenty Minutes Into the Future (on-screen dates, though, put it in the Present Day). The show (and its spinoffs) have given rise to what legal professionals call 'The CSI Effect': the necessity of compressing what would normally be months worth of delicate and time-consuming lab work into a 40-minute television episode causes similiarly 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.


 * The CSI Effect
 * Lampshaded in an episode where they become the subject of a Show Within a Show and mention that everything is edited together to make it look faster.
 * Also lampshaded in a later episode when Hodges mentions that he's convinced everyone that most of the advanced equipment he operates takes twice as long to work as it actually does in order to get more free time.
 * Fingerprinting Air
 * Note that on many occasions the characters complain about the lack of useful fingerprints, and sometimes the fingerprint collected doesn't match anything on the Magical Database.
 * They subverted this in one episode - a cleanly lifted print in an old case is shown to be fabricated because there was no way that it could have been lifted from the surface claimed (an alligator-skin wallet).

"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?"
 * A-Team Montage: As the various forensic specialists build a case.
 * Absentee Actor: 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' "A Christmas Carol" in Providence, R.I. The episode "Gum Drops" was changed when Petersen left town due to a death in the family. The focused 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 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 offical 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.
 * Accidental Hero: Witnesses who unknowingly obtain or provide useful evidence have made life infinitely easier for the CSIs on multiple occasions.
 * Affectionate Parody: In one episode, to Darker and Edgier reimaginings of classic scifi shows.
 * All Girls Want Bad Boys: 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 Draco in Leather Pants. His harem even go so far as to.
 * All Psychology Is Freudian:
 * Episode "4x4"

"Grissom: Well, Freud said that the only unusual sexual behavior was to have none at all."
 * Episode "Fur And Loathing"

"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 "Lab Rats"


 * 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.
 * Ambiguous Disorder: 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.
 * And Starring: Paul Guilfoyle gets an "And", Robert David Hall a "With". Laurence Fishburne - because he is, well, Laurence Fishburne - goes first in the order. Ditto with Ted Danson.
 * Applied Phlebotinum
 * Ascended Extra: Nate Haskell, the Dick and Jane Killer.
 * Autopsy Snack Time: Given a Take That 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."
 * Bait And Switch Answer: 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, "No, I ran over my daughter. Ten years later, and she still walks funny." Another investigator listening in barely stifles her laughter.
 * Beastly Bloodsports: "Lying Down With Dogs", where a wealthy humanitarian was found dead and then found to be involved in dogfighting.
 * Be as Unhelpful as Possible: 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 the pragmatic thing. (But again, Truth in Television; police expect ordinary people to get angry when accused of crimes they didn't commit.)
 * Beeping Computers: Not so much used as abused.
 * Berserk Button: 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....
 * Big Blackout: "CSI Unplugged"
 * Big Eater: 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.
 * Bitter Almonds: Subverted brutally: 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!
 * Black Blood / Alien Blood: In Season Eight's The Theory of Everything, a number of dead people wound up with avocado-green blood.
 * Black Comedy: Pretty much a given in a show about police officers and CSIs dealing with death on a daily basis.
 * Blonde, Brunette, Redhead: Brody, Sarah, and Catherine within the show ; the female leads across the spinoffs there's blonde Calleigh and brunettes Stella and Danville.
 * Male leads: Las Vegas has white-haired Grissom and DB; brunette Mac and redhead Horatio.
 * Blood Is the New Black: "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.
 * Blood on These Hands
 * A Bloody Mess: In "Alter Boys", a suspected blood stain turns out to be red sauce.
 * Bodybag Trick: 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".
 * The Boxing Episode: "Fight Night"
 * Brain Bleach: 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.
 * Brains and Bondage: Grissom's one-time potential love interest Lady Heather was an intelligent woman who ran an S&M club.
 * Breather Episode: Several, usually with the death turning out to be accidental.
 * Broken Bird: Sara Sidle has a pretty serious case of this.
 * Broken Pedestal: Catherine's mentor
 * Bullet Time: Commendably, they waited until Morpheus had thoroughly settled in before showing a bullet-time extravaganza (complete with The Men in Black}!).
 * Bunny Ears Lawyer: 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.
 * Buried Alive: Nick in "Grave Danger"
 * And Laura Garas in the third episode.
 * California Doubling
 * Call Back: Catherine's  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.
 * Calling the Old Man Out: Catherine, after Lindsey is kidnapped, and a few other times as well.
 * Call It Karma: 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.
 * Canon Immigrant: Sqweegel, who originated in Anthony Zuiker's digital novel "Level 26".
 * Can't Get Away with Nuthin': 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 Smug Snake 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 perp.
 * Can't Get in Trouble For Nuthin': 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.
 * Celebrity Paradox: In an episode of the early seasons, we can see the Myth Busters 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."
 * Celebrity Star: Many episodes feature at least one.
 * Chuck Cunningham Syndrome: 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.
 * Until now...
 * City of Adventure: It IS Las Vegas after all.
 * The Collector of the Strange: All the creepy crawlies in Grissom's office. There's also an irradiated fetal pig.
 * Color Motif: 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.
 * Comatose Canary: Used straight on the original show; subverted on CSI: New York
 * Comedic Sociopathy: Hodges, who would make a fine Magnificent Bastard if he weren't so grotesquely inept at everything that didn't involve forensic science.
 * Commuting on a Bus: Sara's right on the line between this and The Bus Came Back. She's listed as a regular, but not in every single episode.
 * Conspiracy Theorist: All of the victims and suspects in "Leapin' Lizards".
 * Consulting a Convicted Killer: Langston seeks the help of his nemesis, serial killer Nate Haskell, to catch the "Dr. Jekyl Killer".
 * Coolest Club Ever: The setting of many of the episodes.
 * Cool Old Guy: DB
 * Corpsing: Speaking of the surgery, Catherine's smirk is probably Marg Helgenberger's own; William Peterson wasn't wearing anything under his hospital gown during the scene. You can infer for yourself the view during Grissom's walking-away part of the scene.
 * Helgenberger said in an interview once that the original idea was to have "THE END" superimposed over William Petersen's bottom as he walked away in the hospital gown, as a joke. Executives nixed the idea as they thought that was too corny and odd for a crime drama series.
 * Cowboy Cop
 * Crazy Cat Lady: The victim in "Cats in the Cradle".
 * Crazy Prepared: Langston. This ends up working to his detriment.
 * Creepy Child: . A given when said child is a pyromaniac.
 * Also the creepy girl from "Unusual Suspect" and "Goodbye and Good Luck".
 * Also the creepy girl from "Unusual Suspect" and "Goodbye and Good Luck".

"Grissom: You going to be able to handle this? Warrick: ...I want this case."
 * Cut Apart: The fifth season finale uses this trope to deal a Your Princess Is in Another Castle moment to a rescue operation.
 * Dark Secret: Often the motive for many of the crimes.
 * Dead Man's Chest: 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.
 * Deadpan Snarker: Count on one (or more) of the cast members making an Incredibly Lame Pun right after the discovery of the body and just before the opening credits
 * Death in the Clouds: Unfriendly Skies
 * Defective Detective: 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.
 * Did Not Do the Research: The real Las Vegas Police have Criminalist level B and A. (all the CSI series merge the roles of criminalist and CSI into one). And it's not LVPD, it's LVMPD, Las Vegas Metropolitan Police Department.
 * Dirty Cop: Vega.Mcquaid and one other FBI agent.
 * Disappearing Box: A woman seems to disappear for real in "Abra-Cadaver".
 * Do Not Call Me Paul: D.B.Rusell. Nobody calls him Diebenkorn. And Julie, who prefers 'Finn', which is short for Finlay.
 * Double Aesop: 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.
 * Downer Ending: "Alter Boys", "Homebodies," "Fracked," "Let it Bleed," and of course "For Gedda." Really, any episode where they can't prove the suspect did anything wrong could be considered this.
 * "Bittersweet" had the culprit turn out to be a
 * Just five episodes later, in "Crime After Crime," it's revealed that.
 * "Trends With Benefits" seemed like it was heading this way  but somehow.
 * Dying Dream:
 * Eagle-Eye Detection: Grissom and Catherine provided the page image at one point.
 * Education Through Pyrotechnics: Complete with Adam and Jamie looking on in one episode.
 * Elevator Failure: Hodges and Henry get stuck when all of Vegas loses power.
 * Embarrassing First Name: 'Diebenkorn' Russell, aka D.B.
 * Enemy Within: Ray, and his struggle not to give into his dark side
 * Enfant Terrible: An 8-years-old not only kills and steals from the victim in, but also tries to incriminate her mother when cornered by the evidence.
 * The 12 years-old in "Go to Hell" is even worse.
 * The young killer in "Unusual Suspects" and "Goodbye And Goodluck".
 * Justin Bieber's character, a teenage Right-Wing Militia Fanatic out to avenge his brother who deliberately almost blows up Stoakes, traps Willows, her detective boyfriend, and a cool bomb tech in a warehouse lined with explosive boobytraps, and convince another adult to go along with all this. Oh, and he was a brat on the set.
 * Enhance Button: 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.
 * Everybody Is Single: 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 Once an Episode.
 * Evil Counterpart: 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 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
 * 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.
 * Extra Y, Extra Violent: Referenced in one episode; a couple knows their son has this condition and constantly treats him with suspicion because of it.
 * Eyes Are Unbreakable
 * Fair Cop: Yowza! Sofia Curtis, Vartann, Lockwood, Sofia Curtis, that lady cop Nick dated for a second in Season 1, Sofia Curtis
 * Faking the Dead: DB and Catherine come back to the morgue in body bags to escape the hitmen who are after them.
 * Fatal Flaw: 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.
 * A Father to His Men: Grissom's markedly paternal leadership style, most visible with Greg, Nick and Warrick DB is getting into this now. His group meetings are "family meetings".
 * Felony Murder
 * Finger in the Mail: One episode featured a man who had found the cut off index finger of his mistress in her apartment. Later, and it is revealed that
 * Follow the Leader: 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 Law and Order Special Victims Unit).
 * Food and Animal Attraction: 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".
 * Forensic Drama
 * Freaks of the Week: In many episodes.
 * Gambit Pileup: "Suckers".
 * The Gambling Addict: Warrick
 * Game of Nerds: Grissom is a baseball fan
 * Good Colors, Evil Colors: Vampire LARPers have red eyes while werewolves have yellow eyes in "Blood Moon".
 * Gorn: The TMI-cam
 * GPS Evidence: 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.
 * Punningly used in the episode Fracked, with literal GPS data.
 * Happily Married: 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
 * Hard Work Montage: 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 Lampshade Hanging: 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".
 * Hazardous Water: Murder in a cloudy swimming pool.
 * Heroic Bystander: 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.
 * High School Rejects: The standard stoners and malcontents that are always the first suspects.
 * Hoist by His Own Petard: 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...
 * Hollywood Exorcism: "Go to Hell". Justified, since the guy performing it is a self-made "priest" with no actual church affiliation and little idea about everything.
 * Hollywood Nerd: EVERYONE. One of them is even supposed to be an ex-stripper!
 * Hollywood Science: 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 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 sex and violence rather than sparkly vampires and werewolves.
 * Hot Mom: Catherine, and Hodges' Mom. Who *is* played by Jaclyn Smith, after all...
 * Hot Scientist: Practically all of the CSIs and the lab techs.
 * Humiliation Conga: Langston's first day is a non-villain example.
 * I Am Not My Father: Ray tried desperately not to become his.
 * Impersonating an Officer: In some episodes.
 * Incessant Music Madness: One case involves a garotted musician.
 * Initialism Title
 * The Intern: Greg, when he decides to leave behind life in the lab to become a CSI.
 * In the Blood: Langston fears he may have a genetically inherited 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:
 * It's Personal: 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:

""You prey on innocent children, and you think we came all the way out here to bust you for possession, you dumb punk?!""
 * 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.

"Sympathetic Murderer: So where did I screw up? Grissom: You killed two people."
 * Jack the Ripoff: "The Execution of Catherine Willows"
 * The Judge: A few episodes center around the CSIs actually appearing in court, so naturally this trope applies.
 * Just a Flesh Wound: Catherine is shot in the side, cauterized with a curling iron, and is still able to keep running from the bad guys.
 * Just One Little Mistake: How most perps get caught.
 * A subversion in the episode "Killer":

"Rule 34a: There's also a CSI episode about it - no exceptions."
 * Karma Houdini: A typical CSI Downer Ending will likely involve one of these, the most horrifying examples being Kelly James from "Homebodies," a robber and rapist who not only walks, but ; the 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 ), but.
 * Karmic Death: 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.
 * 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.
 * Killed Off for Real:, complete with Personal Effects Reveal and Meaningful Funeral. Holly Gibbs.
 * Killer Rabbit: Can we ever look at cornmeal the same way?
 * The Killer Was Left-Handed: Repeatedly, both with literal left-handedness and with problems with DNA in saliva.
 * The Lab Rat: Greg Sanders, whose nickname at Television Without Pity inspired this entry's title. 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 Episodes with the appropriately-entitled Lab Rats and the hilarious "You Kill Me".
 * Unlike most Lab Rat characters on the CSI shows, Hodges is quite content to remain indoors and hates going into the field.
 * Lampshade Hanging: 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"
 * Last-Name Basis: Grissom (even by Sara, his girlfriend/wife), Hodges, Brass, Ecklie, Mckeen, occasionally Russell. Julie prefers 'Finn', short for her last name, Finlay.
 * Left Hanging: 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.
 * Lethal Klutz: 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.
 * Like Brother and Sister: Gil Grissom and Catherine Willows
 * Limited Advancement Opportunities: 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.
 * Locked Room Mystery: A more diluted form sometimes appears in a Police Procedural where the puzzle is eventually unraveled by an eccentric protagonist using more obvious clues and Applied Phlebotinum.
 * Long Runners: Eleven seasons and counting.
 * Lower Deck Episode: You Kill Me and Lab Rats, both featuring the lab techs.
 * Luke, I Am Your Father: 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 old Vegas) murdered; they managed to patch things up a little  and she now refers to him as "my dad".
 * Mad Doctor: 'Doctor Jekyll'
 * Magical Database: 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 Lampshade Hanging 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. Not the CSI unit itself.
 * This is Truth in Television. 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.
 * Don't forget the software/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 it's 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.
 * The Main Characters Do Everything: 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.
 * Somewhat justified as the showrunners say they simply do this to keep the main cast involved without tailspinning into Loads and Loads of Characters. Fans of the show usually let this go by keeping the mantra in mind.
 * Mama Bear: Catherine "Don't mess with Lindsey" Willows.
 * Married to the Job: Both Sara and Grissom.
 * The Mengele
 * Midlife Crisis Car: Lampshaded.
 * Mistaken for Cheating: 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.
 * Monster Fangirl: Nate Haskell's "fiancée" in "Targets of Obsession".
 * Mood Lighting
 * To the point of absurdity; autopsies and lab work are often performed in near total darkness!
 * Ms. Fanservice: Catherine and, briefly, Riley. Wendy might also count.
 * Ronnie, Sara's swing shift partner, in "The Chick Chop Flick Shop."
 * Mulder Moment: "Fur And Loathing". The normally sexually-open Catherine is weirded out by the Furries while Grissom is typically intrigued.
 * Murder-Suicide: 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.
 * The Murder After: Warrick and a stripper who is found dead in his car.
 * Murder.Com: Grave Danger
 * My Card: The investigators will often give a witness their card and say "call me if you remember anything."
 * Myth Arc:
 * The "Miniature Killer".
 * And the Bathtub "Suicides".
 * Dr.Jekyll
 * Nate Haskell
 * Nausea Dissonance: 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 Call Back 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.
 * Necro Cam: 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 referred to as TMI Cam.
 * Need a Hand - or A Handjob?: 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.
 * Never Suicide: 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.
 * 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.
 * "Trends With Benefits" starts out looking like the real-life suicide of Tyler Clementi (see Ripped From The Headlines), but it turns out.
 * Night Swim Equals Death: Too many episodes to list. It's usually signaled by finding the body floating in the swimming pool.
 * No Celebrities Were Harmed: Hilariously averted in volume 6 of IDW's tie-in comics. The story ends with them carting off for the attempted murder of Joe Quesada.
 * Noodle Incident: DB and Finlay's past. Something caused them to become estranged for years.
 * Not Proven: If an episode wants a Downer Ending, this is usually the way it goes about.
 * Obfuscating Disability: "The Two Mrs. Grissoms"
 * Once Per Episode: DB will mention his wife. Or call her. Or both.
 * One Steve Limit: Averted with David Hodges and David Phillips.
 * The Only One: 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.
 * Open-Heart Dentistry: In "Willows in the Wind", Doc Robbins (a pathologist) has perform impromptu field surgery on Catherine; cauterising a gunshot wound with a curling iron.
 * Orifice Invasion / Orifice Evacuation / Chest Burster: Rats seem to like getting inside corpses in this show.
 * Our Ghosts Are Different: I guess they're technically ghosts: 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 he got to see his newborn son for the first time.
 * Papa Wolf: The occasional suspect, especially in the case of an Asshole Victim.
 * Grissom also gave Catherine's abuse ex-husband an Oh Crap moment when said ex tried to bully Catherine.
 * In fact, Grissom tends to go Papa Wolf whenever his team are at risk of harm, for all he usually comes across as emotionally distant.
 * Paper-Thin Disguise: By the Diabolical Mastermind 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.
 * The Perfect Crime: In "Working Stiffs," a lowly office drone makes a seemingly perfect get rich quick scheme.
 * Played straight whenever they don't get the perp, though special mention goes to "Alter Boys", an ep with one of the most remarkable Downer Endings in the show.
 * Perp Walk: Almost at least Once an Episode.
 * Pet the Dog: A posthumous one for 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.
 * Plucky Comic Relief: 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 Lab Rats.
 * Police Are Useless: 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, weilding his gun all over, yelling at the top of his lungs, and just seven feet away. Cops catch up to Ray and... arrest Ray. They somehow miss the screaming madman on a nearby platform with a big gun.
 * Poorly-Disguised Pilot: CSI did this to launch CSI: Miami, which in turn launched 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 ) 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 Professor: Ray.
 * Put on a Bus: Sara and Grissom, presumed retired for good, although Grissom did have a cameo in season 11 "The Two Mrs.Grissoms".
 * Catherine
 * Well, until Sara returns for a few episodes in Season 10.
 * And is now part of the regular cast again in Season 11-a borderline between this and Commuting on a Bus, since she is only in some episodes.
 * Which has resulted in Wendy (Liz Vassey) getting on the bus.
 * Sofia and Riley also make quick exits even after getting promoted to the titles.
 * Quip to Black: The CSI examples are famous.
 * Grissom started the trend, but, to be fair, it was CSI: Miami that took it to a (much cheesier) new level.
 * Rasputinian Death: the episode Ending Happy - played for comedy!
 * Real Life Writes the Plot: Two of the original CSI series' eps had to be rewritten to accommodate actor absences at the last minute. 'Gum Drops' originally had Grissom as the character believing Cassie was still alive, but William Petersen had to miss the episode due to a death in his family. So Nick was shifted into the lead. More recently, in 'Genetic Disorder', Greg had to be shifted into the lead role intended for Nick because George Eads was attending his father's funeral.
 * Real Song Theme Tune: "Who Are You", by The Who
 * Reckless Gun Usage: Nick Stokes investigates how a woman got shot with no evidence of a shooter anywhere near. The answer is that . When they arrest him, he protests it was an accident and Stokes contemptuously responds
 * Redemption Equals Death: Keppler killed an innocent man on the word of a corrupt cop. Guess what happens in the episode that outs the secret?
 * Revolving Door Casting: Seems to slowly be heading towards this with the original cast gradually leaving the show and replacements being brought in over time.
 * Ripped from the Headlines:
 * "Unfriendly Skies", inspired by the Jonathan Burton case and aired only months after the incident.
 * "Anatomy of a Lye", based on the Gregory Biggs case.
 * "After the Show", an almost word for word retelling of the 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 suicide of Tyler Clementi who was outed by his roommate with his webcam, with a twist:
 * Run for the Border
 * Running Gag: Mentioned by name by Hodges in 'You Kill Me'
 * Sacrificial Lamb: The series began with a Naive Newcomer 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 New Meat.
 * Sarcasm Failure: When Grissom doesn't do the Quip to Black.
 * Scary Black Man: Several of these have been suspects over the years.
 * An amusing subversion came from a black teenage gangbanger and Smug Snake, who tried to use this trope to intimidate Warrick. Warrick, of course, wasn't the least bit impressed.
 * Science Hero: Grissom and, later, Ray.
 * Seeker Archetype: Grissom again.
 * Serial Killer: The Miniature Killer, Doctor Jekyll, the Blue Paint Killer.
 * Season 1 alone had three: Paul Milander, the I-15 Killer and the Strip Strangler.
 * Serial Killings, Specific Target: In one episode, a comedian dies from drinking a poisoned bottle of water. Then a kid dies from drinking the same brand.
 * Doctor Jekyll, when finally caught after a season-long killing spree, was in the process of murdering the true object of his rage-  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.
 * Serious Business: Off the top of my head: the Furry Fandom, Scrabble, eating contests, and vampires vs. werewolves LARPing.
 * Robot Rumble!
 * Sex Is Evil: 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 Crime and Punishment Series, really, as the only time the characters usually encounter alternative lifestyles is when there's a grisly murder involved.

"Catherine to Grissom: (while helping the latter put on a tie) "You need a woman.""
 * 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.
 * Shipper on Deck: DB seems to ship Morgan/Greg, seeing as how he's called Greg her boyfriend on at least one occasion.
 * Ship Tease: Grissom and Catherine playfully flirt with each other and it never goes anywhere. To wit:

"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, when Catherine returns from Miami in which she helped investigate a case there, "I missed your tush".
 * The "How can I help?" scene (see above for details).
 * There have also been hints towards possible Nick and Sara - Word of God 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:

"Sara: "Do you want to sleep with me?" Gil:' "...Did you just say what I think you said?""
 * Grissom and Sara themselves in the first season.

"Reporter: Do you know what "fracking" is? (it's explained here, which appears to be the episode's inspiration) Langston: Sounds like a sci-fi expletive."
 * Although that was a Rule of Drama 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.
 * Shot to the Heart: Doc Robbins does this in one episode, where a guy revives on his table.
 * Shout-Out: Hodges and Langston do a very-thinly-disguised Myth Busters-style experiment, complete with Plexiglas shield. All they needed was the "3, 2, 1!" part.
 * In an earlier episode, Savage and Hyneman make a cameo observing such an experiment.
 * Actually - it was 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 Serial Killer at a place called Black Mesa.
 * Hodges cat is called Kobayashi Maru
 * Boomer and her creator look on in horror as a Star Trek expy is given the Darker and Edgier treatment.
 * The 2009 season opens with an extended Bullet Time extravaganza, complete with Morpheus kicking an "Agent" through a window.
 * "Blood Moon"'s Cold Opening looks and sounds a lot like True Blood's opening titles.
 * "Fracking" also happens to be detective Starbuck's second episode and has a direct reference:

"Hodges: Trust me, I'm an expert."
 * Also includes an Erin Brockovich reference to Catherine (she's not Erin Brockovich, but she was a client).
 * Several Quentin Tarantino motifs are used in the Season 5 finale he directed and co-wrote: Warrick and Nick have a Seinfeldian Conversation before going to work, Grissom has a rare piece of Lone Ranger memorabilia, there's a Death as Comedy moment, 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."
 * The Show Goes Hollywood: "Hollywood Brass" and "Two and a Half Deaths".
 * Shown Their Work: More often than you think; it's the editing that turns it into Hollywood Science. There's also the episode involving a not!Star Trek convention, which is filled with references, including the Picard Maneuver. The shirt-tugging one.
 * Shut UP, Hannibal: Langston had several moments like this with Nate Haskell.
 * Sick Episode: Grissom's Divine Comedy
 * Side Bet: 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 shouldn't have been participating...)
 * There's also been a whole episode with a Running Gag 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.
 * Skinny Dipping: "Fracked" opens with three teenagers skinny dipping in hot spring. They discover a dead body floating in it.
 * Slasher Smile: [[media:fuelriffic_Rylan_Gauss_2_1515.jpg|Rylan Gauss]] in "418/427".
 * Snuff Film: Snuff
 * Spanner in the Works: 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 Dead Man's Chest 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 Heroic Bystander catching a Peeping Tom who also turns out to be a serial rapist, have all given the CSIs invaluable help over the years.
 * The Spock: Grissom
 * Spontaneous Human Combustion: One episode has a subplot dedicated to SHC. After finding a charred corpse with all the hallmarks of Real Life 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 aboutthe Wick Effect, congratulated the experimenters on a successful experiment, and then told them that this was coming out of paycheck since it was unnecessary.
 * Stage Magician: The Amazing Zephyr from "Abra-cadaver".
 * 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.
 * Suspiciously Similar Substitute: 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 Team Dad 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 Team Dad element about him,and has some of the sense of humor at times.
 * Swallow the Key: In "Abra-Cadaver," the killer, a Stage Magician who was perfectly willing to kill his family members for the sake of illusions, does this at the end (although Grissom did think to check his mouth).
 * Sympathetic Criminal: Eventually subverted--the bank robber claims he's doing it for his family, but he's lying.
 * Sympathetic Murderer: 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 The Far Side, complete with the wife wearing cats-eye glasses.
 * Then there was the guy from "Lying Down With Dogs" who
 * Quite possibly
 * Take a Third Option: 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.
 * Take Five
 * Television Geography: The frequent presence of lush greenery and vegetation, and moderately frequent rain, in desert Las Vegas on CSI (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 "Jackpot" and another in the 2004 season premiere.
 * Themed Aliases: In "Living Legend", the killer uses aliases that the names of movie serial killers: Michael Myers, Pamela Voorhess and F. Krueger.
 * Time-Delayed Death: 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 tries to walk home, but collapses and dies... right under the tires of a cab. The cabbie then.
 * 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 undertsandably confused.
 * Token Minority: Warrick Brown until 2008. This role was then played by Dr Raymond Langston (Lawrence Fishburne). Now, there isn't one (after 2011)
 * Tonight Someone Dies
 * True Love Is Boring: Grissom and Sidle. After years of UST, their separation just comes somewhat out of left field.
 * Trust Me, I'm an X: From "The Theory of Everything:"


 * And then Wendy kicks his ass.
 * Wendy kicks his ass frequently. The first time he doesn't completely screw up in a Lab Rat Episode is when he finally gets a kiss.
 * Two Lines, No Waiting: Nearly every single episode. Occasionally the characters will find out halfway through the episode that the crimes they are investigating are tied together. Some episodes pull this off better than others.
 * Underside Ride: In "XX", a woman tries to escape from a prison in this way and suffers Ludicrous Gibs from getting caught in the moving parts..
 * Unfortunate Name: Diebenkorn. Not a punny or risque one, but still one that he'd probably like to forget.
 * Useless Security Camera: 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.
 * The Verse: In addition to its two spinoffs the show has also shares a universe and crossed over with fellow CBS procedurals Without a Trace and Cold Case.
 * Villain Episode: Killer and Working Stiffs
 * We Are Everywhere
 * Welcome Episode: Subverted in a major way by having a Welcome Episode premiere which ended with Naive Newcomer Holly Gribbs getting shot dead.
 * Then played straight when Sara Sidle is brought in to replace her/act as an independent investigator.
 * Well-Intentioned Extremist:
 * Whip It Good: Lady Heather.
 * Working the Same Case: Frequently
 * Wrong Genetic Sex: 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.
 * You Fail Biology Forever: Particularly egregious in the shows' portrayal of fingerprints, which are not retrievable from all surfaces (like many textiles), are not left if the actual finger does not make contact, and cannot be made through gloves...
 * 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.
 * You Look Familiar: Three of the franchise's primary actors (the ones in the opening credits) have appeared on all 3 series (there may have been more with the one time guest stars, a lot have done at least two) Lawrence Fishburne, David Caurso and Carmine Giovinazzo. But only characters Ray Langston and Horatio Caine have been on all 3 series since Carmine's guest appearence on the original CSI was 2 years before he began playing his CSI: NY character. Word of God says the guest role didn't influence the CSI NY casting.
 * Marlee Matlin appeared in a role each in CSI and CSI NY.
 * A.J. Buckley, who plays Adam on CSI New York, appeared in one episode of the original CSI series beforehand.
 * Fans of both Xena: Warrior Princess and Firefly may recognize Lady Heather as a rogue Amazon and brothel madam, respectively.
 * You Need to Get Laid: When Nick jokingly tells his nerdy Lab Rat coworkers they need to get a girlfriend, it backfires both times. David reminds Nick he's engaged, and Archie just scoffs, "You first!"
 * Your Other Left: "Alter Boys"
 * Youth Is Wasted on the Dumb

The CSI video games provide examples of (in addition to many listed above)
 * Art Evolution: Just look at the graphics for Fatal Conspiracy, and then look back at the very first CSI game. Yeah...
 * Back Tracking: 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.
 * Brick Joke: 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.
 * Cliff Hanger / Downer Ending: The ending to Fatal Conspiracy.
 * Early Installment Weirdness: 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.
 * Face Heel Turn: Practically a fleet of police officers and undercover agents in the game Fatal Conspiracy.
 * The Other Darrin: Marg Helgenburger and Jorja Fox do not voice Catherine or Sara in most of the games.
 * Padding: They REALLY make you work to match fingerprints, DNA, and chemical samples.
 * A Winner Is You: 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 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.