I Never Said It Was Poison

""It's called guilty knowledge, and juries eat it up.""

- Captain Stottlemeyer, Monk

The usual response to a perp Saying Too Much. The perp, while maintaining his innocence, reveals information he could not possibly have known if he were innocent, usually the specific details of a murder. It can take the form of a Suspiciously Specific Denial. For full dramatic effect, the interrogator does not immediately point out this discrepancy, but continues the interview, often saving the kicker to the very end, as a sort of And Another Thing epilogue. Even more dramatically, the interrogator may insist it wasn't poison and then probe the perp's reaction to this lie.

This trope must be handled carefully; when sloppily done it's likely to turn what should be a dramatic moment into a Fridge Logic. The most common mistake is making the piece of information something that the person who makes the "slip" could reasonably have found out without committing the offense. The second most common mistake is making the "slip" an assumption that could reasonably be made even by an innocent person.

One of The Oldest Tricks in The Book, and very much Truth in Television. Police investigators almost always hold back specific details of a crime and/or crime scene when making public statements. This has the dual benefits of possibly identifying a suspect and helping separate valid witnesses from useless leads. (Knowing these details may not automatically make someone the guilty party, but it's a big clue that they were at least present for the crime.) This is one of the reasons civil rights advocates warn people never to talk to the police without an attorney present. Even an innocent person can make assumptions about a case, and look guilty if they turn out to be right. For example, you might say, "I don't even own a gun," when you were never told the victim had been shot. It's even possible for the police to "forget" (or to actually forget) while testifying that they actually did give you the information before the interview began. Then you're screwed.

This trope can be invoked in works during a character's confession. Innocent characters attempting to take the fall for a crime they did not commit will probably guess facts about the crime that may not be true. If the facts are incorrect, they will be most likely be called out on it immediately or in a And Another Thing manner. If the character is guilty, they could willingly give information only the perpetrator would know. This could be played to induce Squick.

See also: Conviction By Contradiction and Bluffing the Murderer

Anime and Manga
"Detective #1: So, you say you have nothing to do with the Black Labor?
 * Happens all the time in Case Closed aka Detective Conan. Things like, "I have an alibi for 8 to 9 pm!" "How did you know when the victim died?"
 * L tries this strategy on Light SEVERAL times in Death Note. Unfortunately for him, Light is too smart to fall for it, always carefully keeping his comments to common knowledge and believable deductions.
 * Sei Arisaka does this in Himechan no Ribon by saying that he knew who Pokota was even though Hime-chan had never told him, which is how she realised there was something more to him than original thought.
 * Liar Game used this too..
 * Not quite the same, but related: In the third season of Sailor Moon, Mistress 9 is posing as Hotaru to talk to Sailor Moon. Eventually, she refers to Sailor Moon by her real name, which tips her off: "Hotaru...how did you know I'm Usagi Tsukino?"
 * Monster has this happen once too. In Episode Six, a couple of detectives are apparently transporting Tenma and Anna Liebert to their police station.(They actually work for Johan Leibert.) Tenma eventually figures this out when one of them calls him "Dr. Tenma" even though he only told them his name and not that he was a doctor.
 * Near the end of the Patlabor Manga, three detectives are interrogating the CEO of a company they're almost certain is the maker of the Griffon (which is still known to the general public as "the Black Labor").

CEO: How many times do I have to tell you? I don't have anything to do with the Griffon! Or do you want me to just admit my "guilt"?

Detective #1: If you did that in the first place, it would have saved us a lot of time. (Turns around) Did you hear that?

Detective #2: Yup.

Detective #3: Sure did.

CEO: What...?

Detective #1: Sir... How did you know the Black Labor is called "Griffon"?"


 * Fushigi Yuugi has this during the Kodoku arc. Tamahome meets Miaka in the place they were supposed to before Nakago placed him under his control. He tells her, quite convincingly, that he only played along with Nakago's plans... at which point he asks her where Tasuki and Chichiri were, in spite of the fact that Miaka never told him Tasuki, whom he didn't even know at that point, would be coming along.

Comic Books

 * Used in Identity Crisis, when
 * In Get Fuzzy, Rob asks who took his package. Bucky says he never saw that sweater, leading Rob to ask "How did you know it was a sweater?" Grounding ensues
 * In Transmetropolitan, our heroic journalist accuses the presidential candidate of killing his aide, to which the response is along the lines of "Of course we wouldn't kill her, she was a friend and a vital part of the campaign". See there how they admit that murdering some people would be okay in their book.
 * Later, The Smiler's campaign manager refers to the assassin as "he". Spider asks how he can be sure the killer was a man if he or she was disintegrated immediately after taking the shot.
 * In Hellboy: Conqueror Worm, local guide Laura Karnstein is leading Hellboy and Roger to an abandoned castle. While making conversation, Laura casually mentions that she read Hellboy's file and was impressed by his past exploits. As they reach the castle, Laura goes on ahead, but Hellboy stops Roger to warn him that Laura couldn't have read his file. Sure enough, Laura is not who she claims to be.

Film
""Damn it. I always do things like that. You never said her name, did you?""
 * Ed Exley from LA Confidential likes doing a variant of this in his interrogations. In particular, he tends to say something about them being guilty as if it were a fact, and note that the person never protests or reacts as an innocent person would. For example, in his first interrogation he tells the perp "It's a shame you didn't pull this a few years ago when you were a minor, you being an adult makes it a gas chamber offense." Later, after he's done and is leaving the room, he stops to say, "You know Ray, I'm here talking about you getting the gas chamber, and you never asked me what this is about. You've got a big guilty sign on your forehead." The kicker though is that
 * Minority Report has the villain realize the protagonists are onto him when he's caught in one of these.
 * In Alone with Her, the tip off that the protagonist has planted surveillance cameras in the house of the girl he's courting is when she rejects him and he starts ranting: "...I did everything for you, but you want to go back? To what? Huh? To being alone? To this empty room? To that brush?" Earlier in the movie, he'd caught a live feed of her masturbating with the hairbrush.
 * In the Harry Potter movie, Barty Crouch blows his cover as Mad-Eye Moody by mentioning the graveyard Harry was sent to before Harry does. It's rather likely he didn't care at that point, though.
 * Also, in the Harry Potter movie, Dobby the house-elf repeatedly does this, accidentally admitting to having, although the last two may have been intentional. Unlike the example above, these were also in the book.
 * Used lightly in ~1408~ when Mike Enslin calls a hotel for a reservation in the eponymous room, which the staff says is unavailable, despite not knowing when he'll be visiting, since they don't want anybody staying in the room ever.
 * Averted in Sleuth; Wyke mocks Inspector Doppler for trying this tactic on him.
 * In Sudden Death, when one of the villains gives himself away, and immediately Lampshades it.

"Mook: Like I told you before, asshole, I don't know no Jack Travis
 * Subverted in the murder mystery Knight Moves wherein the protagonist knows the latest word in the serial killer's message without being told directly, because the killer namedropped a chess master and the word is that master's watchword.
 * Although the protagonist never realizes it and the film never makes a point of it later on, early in Red Eye Jack ends up letting slip the name of the protagonist's father, which at that point she had never told him.
 * Played straight so often in The Woman in The Window that it stops being suspenseful and becomes hilarious; the guilt-ridden professor lets slip every possible detail, including knowing the man was murdered (when the body hadn't turned up yet), knowing where the body was placed, that it happened at night, etc. His friends are so dense that they wave off every comment and never suspect him, but you would think he'd just learn to keep his mouth shut, especially when having casual conversations with the district attorney.
 * In The Count of Monte Cristo, Mercedes realizes that the mysterious Count really is Edmond when he tells her that "Edmond Dantes is dead." She had told him that her lover Edmond was dead, but not his last name.
 * A version of this is in the movie Patriot Games, after Jack Ryan's IRA informant gives him pictures of the people who had attempted to kill Ryan (and in a separate attack, his wife and daughter). Jack's superior dismisses the information, believing that mole is trying to mislead Jack. "All he has to do is show you a few pictures of a girl... Jack realizes he never told the man he was looking for a female assassin and realizes the information must be legitimate.
 * In Wild Child, when Poppy is before the Honour Court for setting fire to the school, head girl Harriet accidentally reveals that she was actually the one who started the fire, by talking about the very specific lighter that Poppy supposedly used when no one has mentioned anything about a lighter.
 * Lethal Weapon 3:

Riggs: Hey, I didn't say his name was 'Jack' - You'd better start telling me more than Jack Shit."

"Chekov: You lie! On Ceti Alpha V there was life. A fair chance-
 * Scream 4:
 * In Godfather 2, Michael realizes that Fredo betrayed him when they were in a Cuban sleazy nightclub, and Fredo said "Watch this part of the act, it's really something", even though earlier Fredo had told Michael that he had never been to Cuba before.
 * In Basic, this is subverted when
 * In Star Trek II the Wrath of Khan, Khan realises Chekov and Terrel meant to beam down to Ceti Alpha VI when Chekov lets slip that he did not know they landed on Ceti Alpha V.

Khan: THIS IS CETI ALPHA FIVE!!!!!!!!

(A few moments and more exposition from Khan later)

Khan: You didn't expect to find me; you thought this was Ceti Alpha VI! Why are you here?"

Literature
"Moist: Look, I know how this sort of thing goes. You just sit here and ask questions and eventually I slip up and reveal something incriminating, right?
 * This happens in Encyclopedia Brown books quite a bit. Not generally for murders, but it happens.
 * One story had Encyclopedia figuring out which member of a gang robbed a grocery store, his only piece of evidence being a knife left stuck into a watermelon. When confronting the gang, one of the members says his knife is an inch longer...despite the knife never having been taken out of the melon, and the watermelon specifically having been described as "huge" so that even the longer knife blade would still be completely hidden.
 * Another Encyclopedia Brown story has someone getting shot in the foot by a BB gun. One of Bugs' friends shows up, and Encyclopedia tells him to run to the kid's house and get his shoe. The kid grabs the correct shoe, and Encyclopedia points out that unless he was the one who shot him, he couldn't have known which shoe to get.
 * We know what you're thinking: There was a 50/50 chance of him getting the right shoe.
 * Or he could have just grabbed both shoes, which would probably have been sitting right next to each other.
 * Another story had a pair of rollerskates stolen from Encyclopedia while the latter was at the dentist. He asks the main suspect (a kid who had a doctor's appointment in the same building) if he was in Dr Vivian Wilson's office. The kid claims "I never heard of him until you mentioned his name" and that he didn't go near Wilson's office because he "had a sprained wrist, not a toothache" meaning that not only did he know that Dr. Wilson is a dentist but that he is a man despite his first name being "Vivian".
 * Also common in Two Minute Mysteries, by the same author - things like "Dr. Smith was murdered, where were you at the time?" "I haven't been to a dentist in years."
 * In Orson Scott Card's Ender's Game spinoff novel "Ender's Shadow," Achilles slips up and tells the other orphans that Poke had been stabbed in the eye, when he couldn't possibly know that. Nice show, Achilles, nice show.
 * Colonel Graff does a slip up on the phone to Bean's caretaker (a very intelligent nun) when he says the name Bean told him about Achilles (pronounced uh-kill-eez). The nun points out that since Bean is from the French section of Rotterdam he would have pronounced it ah-sheel and correctly calls him out for spying on Bean's journal.
 * This happens in the third Brother Cadfael book, Monkshood, but inverted. A man caims that he didn't stab his (poisoned) stepfather.
 * In a short mystery story called "True Lies," starring Lieutenant Johnson and Sgt. Bolton, the genius detective sergeant has narrowed down the possible murderers to two, but doesn't know which one. Since he thinks his lieutenant partner (who is the Narrator, and who would be Too Dumb to Live if he didn't know how to hide it from his fellow cops) is the genius detective, and so is dependent on him for his own genius, he asks the lieutenant for the solution. Our narrator doesn't know and is eating dry granola, so he chokes and says (as an excuse) "Tense!" This gives the sergeant the solution; the murderer was the one who referred to the victim in the past tense before it was generally known that she was dead.
 * Timothy Zahn's last book of The Thrawn Trilogy, The Last Command, features
 * In Jo Walton's novel Farthing, the murder victim appears to have been stabbed. The police forensic techs figure out that he actually died of carbon monoxide poisoning, but don't reveal this to the press. A bit later, one character reveals that they know that the victim was gassed.
 * Played with in Terry Pratchett's Discworld book Night Watch. After an antagonist officer tells Vimes of a break-in, Vimes asked what had been stolen. The other officer tries to invoke this trope, replying "Did I say they stole anything, sir?" and Vimes shuts him down with "Well, no, you didn't. That was me jumping to what we call a conclusion. Did they steal anything, then, or did they break in to deliver a box of chocolates and a small complimentary basket of fruit?" (Although to be fair to the officer, Discworld is home to crimes such as 'breaking and decorating'.)
 * Used more conventionally in the earlier Guards! Guards!, in which Lupine Wonse's immediate response to Vimes reporting the destruction of the Elucidated Brethren's headquarters was a suspiciously specific "Any of them get out?" Because Vimes was distracted, he doesn't pick up on this until a Eureka Moment later on.
 * Inverted in Feet of Clay when Carrot becomes sure that Dorfl didn't kill Dr. Hopkins when he agrees to Carrot's statement that Dorfl beat him to death with an iron bar, when in fact he was killed with a loaf of dwarf bread.
 * Vimes uses it once again in Thud when talking to the Troll crime boss Chrysoprase. Chryosprase lets slip that his knowledge of a crime scene is greater than what the public would know. When Vimes calls him out, Chrysoprase dismisses the accusation as gossip that he heard from the Dwarfs. Or well, had Dwarfs beaten up or threatened until they told him. He did in fact have no connection to it.
 * Used in Going Postal. Moist is being interrogated by Carrot, all while under the guise of being an upstanding pillar of the community businessman. When he tries to shut Carrot down due to him, Moist, being aware of this trope...

Carrot: Thank you, sir.

Moist: For what?

Carrot: For telling me that you know how this sort of thing goes, sir."

"Ruth Rose: And your fingerprints are on the mantel where you stole the Christmas card!
 * In Graham McNeill's Warhammer 40000 Horus Heresy novel False Gods, Loken knows that Erebus is lying to him because he pointed out that the interex had accused them of stealing a kinebrach's sword -- and in fact, the interex had only accused them of stealing a weapon.
 * Inverted in A Widow for a Year when the policeman deliberately gives the press false information about a murdered prostitute, saying she was killed WITH a struggle when there was no struggle. This enabled him to dismiss the two men who confessed as they were covered in bruises and scratches.
 * Used near the beginning of The Haunting of Alaizabel Cray- the hero finds a young woman in the part of London infested by gribbly things, and asks the governor of a local mental asylum if he's lost any patients- he mentions her being found in the Old Quarter, despite not being told. In this case, it could be a reasonable assumption but the hero decides to be careful and gives a false description-
 * This is how George Smiley discovers The Mole in the Secret Intelligence Service in John Le Carre's Tinker, Tailor, Soldier, Spy: the man in question turned up at the Circus with not enough information about the unfolding Operation Testify crisis for him to have got it from the radio report, but too much to have overheard it from a phone conversation.
 * In the Thursday Next book First Among Sequels, Thursday and Spike accuse a plumber of stealing money from a pensioner. His boss joins in with the accusation, saying "A thousand pounds, from a defenceless pensioner? How could you?" Thursday and Spike had never mentioned the amount.
 * Reversed in Tom Clancy's Clear and Present Danger, when the FBI is investigating the mistreatment of prisoners on a Coast Guard ship- he says that one of the prisoners was executed (he wasn't, but they staged an execution by hanging to get a second prisoner to confess everything) to which the captain replies "We captured 2 prisoners, we gave you 2 prisoners, alive, so who did we shoot?"
 * In one of the Fire Thief trilogy, the Avenger almost pulls this off and discovers the boy he is talking to is helping Prometheus when the boy mentions the shopkeeper looking for a spade (to dig up some buried treasure). But the boy quickly says he was running down the street shouting "half a million dollars for a spade."
 * A Nancy Drew book had a Jerkass character being poisoned, but ultimately recovering. A few days later, his ex-girlfriend taunts him about as he tries to eat breakfast, stating, "You know, poison doesn't have to be a powder. Something could have been injected into that orange. . ." The only way she could have know what type of poison was used was if she was the assailant. Just change "doesn't have to be" to "wasn't" and you've got an admission of guilt that still wouldn't stand in trial.
 * The Three Investigators had a case involving a whale where a suspect accidentally blurted out its species.
 * On another occasion, someone asks what the "???" on their business card means. This is a Once an Episode thing which wouldn't normally be significant, but one of the group notices that they didn't actually read the card, and must have seen it before.
 * Used in one children's mystery, in which an unknown student was sending anonymous letters to the teacher, telling her all of the mean-spirited things said behind her back. This causes the teacher to be miserable and make all of the students feel horribly guilty. The only clues are that the mysterious student spells "sincerely" incorrectly and leaves a glob of ink as a signature. Eventually, they narrow it down to one person and trap her by innocently bringing up the ink blob. She blurts out "That's not an ink splotch, it's the shadow -". Busted.
 * In Katherine Kurtz's The Quest for Saint Camber, a member of the secretive Camberian Council is found dead in a secret passageway of the king's palace. In a conversation with Nigel (King Kelson's uncle/regent/heir presumptive), his eldest son Conall says the victim's entire name, which the younger man is not supposed to know. Nigel realizes Conall had been secretly working with the dead man (to obtain arcane powers reserved for the monarch) and killed him in that stairwell; Conall attacks his father with those powers and leaves him in a coma.
 * At least one of Tom Savage's stories (specifically ) has the protagonist mention something he shouldn't have known. This leads to a Tomato in The Mirror scene with a literal mirror.
 * Actually, there's some questionable writing here on Savage's part - the protagonist gives information that could easily be explained away, while the antagonist is the one who gives far too much information to authorities - yet the book acts like the protagonist has said something absolutely incriminating.
 * A case of the villain inadvertently using this against the protaganist occurs in Scorpia, when Julia Rothman tells Alex that Scorpia intends to activate a bioweapon that will kill a significant portion of the population. Alex, knowing that the weapon is designed to specifically target schoolchildren, blurts out that they can't murder children, causing Rothman to realise that Alex is a triple agent for MI 6, and that MI 6 have figured out how the weapon operates.
 * In the Father Brown short story The Green Man, the victim is an Admiral who is found dead in a pond close to his home, on the evening when he was expected to return home from a longer sea voyage. Upon being told that the Admiral is drowned, the murderer asks:  Note that Father Brown is older than radio. If the Admiral had drowned at any time during the voyage, his family would probably not have found out until his ship came back to England.   Father Brown bites his tongue at the actual tip-off, but this trope comes into play in the big reveal at the end.
 * At the end of the A to Z Mysteries book The Lucky Lottery, the three main kids confront their prime suspect over a stolen lottery ticket.

Dot Calm: You're crazy, kid. I was wearing glov..."


 * In the Waco series by JT Edson, Waco uses this trick a few times to trip up a killer.

Live Action TV
"Gideon: Is that why you stabbed him in the groin?
 * In the various Law and Order shows, the detectives will often hold back certain details of the crime from the press, so they can test the veracity of any account from a suspect or witness. As many times as it's used to trip up the guilty, it will also expose someone attempting to confess falsely. For instance, a father taking the rap for his son's crime, not being able to describe at his allocution in court how and where he hit the victim.
 * Also Truth in Television not just for debunking people trying to protect the "real killer," but also, the higher profile a case, the more likely it is to have kooks falsely attempting to confess. Either because they're insane, they want attention, have avoided punishment for something else and want to atone out of guilt or they just enjoy fucking with the police.
 * Avoided in one episode when McCoy decides to go through with a generous plea deal with a suspect that covered "miscellaneous crimes" after the police told him the suspect's partner was dead. He exploited a loophole that allowed him to charge the defendant with crimes the DA didn't know about before making the plea; since the police never said the partner was murdered, he had no way of knowing his death was a crime.
 * Explicitly lampshaded in Law and Order LA when the prosecutor asks the defendant, a Secret Service agent, if based on his long career and investigations that he'd agree that a suspect displaying knowledge of the crime was probably guilty. Defendant says yes. Prosecutor presents the text messages (sent from a smartphone they'd found concealed in the defendant's cell) to the victims' husband/father revealing information that only someone present in the house just before the attack would have known.
 * This is brutally subverted in an episode of Law and Order Special Victims Unit. After a lengthy interogation, Olivia catches a suspect mentioning a scarf that only the rapist would know about. The man confesses, is convicted and sent to jail. Eight years later it is revealed that the man is innocent. Olivia realizes that she must have mentioned the scarf early in the interogation and forgotten about it. She essentially browbeat a tired and confused man into confessing to something he never did.
 * Standard operating procedure in Criminal Minds as well.
 * Best use was probably The Fox, where the killer, profiled as probably having OCD, has a minor Freak-Out during questioning when he notices the pictures of his victims are out of order.
 * The episode "A Real Rain":

Suspect: It's what he deserved."


 * The victim had been stabbed in the head.

"Monk: How did you know she was wearing a bathrobe? No one said anything about a bathrobe!
 * In yet another episode, their usual plan of withholding things from the media was thwarted by a leak and they had to find it quickly.
 * In one case of CSI, Brass (after the fact) realizes that he should've been suspicious of the husband of a woman drowned in the bathtub from the beginning when he remembers that, while she is being carted away by the EMTs and it's not yet clear whether she is going to make it or not, the husband says: "I loved my wife." Whoops!
 * Happens on Monk. In one episode, the Captain shows a gun that had been used to murder the victim to the victim's friend. The friend points out the cracked handle on the gun and says that the victim was bludgeoned to death (which he was). Near the end, the Captain realizes that anybody who didn't know would assume that the victim had been shot, not beaten, and arrests him as he's about to kill Monk.
 * When an infant in foster care is found handling a kidnap victim's severed pinky in the park, Monk deduces at the very end that it was  one of whom was told the child found a finger but replied back that he found a pinky.
 * The page quote comes from an episode where the killer points out that the police already had a suspect, calling him a "chain-snatching, dope-sniffing punk." Leland points out that the police hadn't revealed that the kid in question had stolen a chain to the public, thus only someone present when it happened could know about it. (On his way back from killing his wife, he broke his tail light. If he got pulled over for it, it would break his alibi, so he had to get it fixed. While he was there, he witnessed the kid robbing the auto shop and realized he was on camera, so he killed the shop clerk and took the camera footage.)
 * There was a hilarious Subversion on the episode where Monk's medication interferes with his deductive talents. Monk attempts to nail the killer with "guilty knowledge":

Killer: You did! Two minutes ago!"

"Suspect: Is that what this is about? You drag me here to see if the guard recognises me? Well, it didn't work! He didn't know me from Adam!
 * NCIS:
 * One of the several clues that a midshipman's training sergeant had been guilty of his murder was that when Gibbs notified him of his (missing-presumed-deserted for several days) student's death, without mentioning that his death was murder, the sergeant's first question was 'Do you know who killed him'?
 * In a later episode, the suspect's wife assures Gibbs that her husband would never shoot a woman in the back. Of course, Gibbs hadn't mentioned to her or her husband how the victim had died.
 * Used in season 3 when a lieutenant working in the Cryptology unit was found murdered. Her boss asks Gibbs about her having shot herself, and Gibbs says later that only two people know how the Lieutenant died... one of her coworkers (who he'd interrogated) and her murderer. He then turns to the boss and asks, "How did you know she shot herself?'
 * An example from season 2: A woman with amnesia comments that "someone bashed that poor man's head in," when no one had told her how the man was killed. Unfortunately, by the time Kate realizes this, it's too late.
 * Subverted on Homicide Life On the Street: In the episode "Bad Medicine," Detective Lewis tells Villain With Good Publicity Luther Mahoney that a recently deceased thug obviously committed suicide. Mahoney scoffs, pointing out that the victim was shot in the back of the head and the gun was left on the table next to him. Lewis gleefully pounces, proclaiming that neither piece of information was released to the public and placing Mahoney under arrest. In the end, though, the state's attorney figures that there are any number of ways Mahoney could have learned it, too many to be beyond reasonable doubt.
 * Inverted on The Wire: The detectives show one of the perps a bag with three guns saying that they found his fingerprints on one of them. The perp knows that they cleaned them, so asks the detectives which one it is. They point to another gun.
 * Another example on The Wire, this one tragic. During an interrogation, Herc accidentally reveals too much about his informant (Randy), which gets the kid branded as a snitch, his house firebombed, his foster mother killed, and generally ruins his life.
 * An example entirely between criminals: Brother Mouzone clues in to the fact that  because   seems to know that there was more than one assailant.
 * Used frequently in Murder She Wrote. In one episode, the suspect is asked to the police station and, while waiting outside the detective's office, is passed by the office security guard (not in uniform). He's then called in, where Jessica tells him her theory. His murder plan involved working late every night so the guard wouldn't know what he looked like, then re-entering the office building disguised as a delivery guy.

Jessica: What makes you think that man was the security guard?"

""Bridget": You're a liar, Malcolm Reynolds!
 * Happened in the Bones episode "Mayhem on a Cross".
 * A suspect in Without a Trace makes a pretty bad one of these. After only hearing a missing man's name and seeing a headshot of him, claims he'd "never hurt a guy in a wheelchair". Whoopsy.
 * In the Firefly episode "Trash", Mal meets an old friend Monty's new bride, an old enemy. They pull guns on each other and fight. After Monty separates them, Mal explains their mutual history to all present, and then:

Monty: ...now I ain't never got to tellin' ya his name."


 * Thereby proving, at the least, that she and Mal weren't strangers, as she had said.
 * Had she not made that mistake, she still would have had to explain why their first reaction upon seeing each other was to pull a gun on each other.

"Harken: Alliance property, too. You could lose your ship, Captain. But that's a wrist slap compared
 * In the episode "Bushwacked" an Alliance official tries to use this one on Mal, telling him they're looking for a brother and sister without mentioning the two are adults. Without batting an eye, Mal pretends to assume he's talking about children.

to the penalty for harboring fugitives. A brother and sister. When I search this vessel, I won't find them, will I?

Mal: No children on this boat.

Harken: I didn't say "children." Siblings. Adult siblings.

Mal: I misunderstood."

"Crown Prosecutor Kaye: Or was it just because he looked like a rapist?
 * Played for laughs in The Games- after taking an Albanian delegation sightseeing and setting fire to one of the members of the delegation's wigs, Gina confesses this to Bryan, who tells it to John... who tells it to a gossip columnist. Gina arrives at his house on the weekend and says she'll lynch Bryan for leaking the story, as she only told him, and John plays along before mentioning the name of the columnist. Gina immediately says 'I never said it was in Manny's column. How did you know it was Manny's column, John?' and he stammers until she gets up and walks out.
 * Used on This Is Wonderland. A white woman beats up a black man, thinking he was trying to rape her. He takes her to court, and she is so expecting the race card to get played that the following conversation ensues:

Defendant: This has nothing to do with him being black!

Crown Prosecutor Kaye: Black? I just said he looked like a rapist. You're the one who attached "black" to "rapist"."

"Killer: Al Mooney is insane! Nobody will believe what he says.
 * Frequently used in Columbo.
 * One episode had him find a witness, but it was a blind man. So they bring the suspect in, and
 * A non-criminal example from The Cosby Show: Claire discovers her favorite mug has been damaged, poorly glued back together, and replaced. Heathcliff expresses his shock that one of the children would put it back in the cupboard. Claire never said it had been put back in the cupboard.
 * Used in the episode "Red Badge" of The Mentalist. However, they already knew who the killer was--they were just getting him to confess.
 * Used to determine the Dean's real murderer in Veronica Mars.
 * Used in a last-second plot twist on Mathnet to uncover the leader of a gang of thieves who rob people's apartments after offering them a free weekend in the Poconos.
 * In the The X-Files episode "Small Potatoes", Mulder stops a seemingly innocent man in mid-speech, saying, "Hey wait a minute, wait a minute: how did you know my name was Agent Mulder?" The man runs.
 * Inverted in Human Target: Chance suspects the cops escorting his client of being the ones trying to kill her contact. They're too clever to let this slip, so he openly mentions an unknown fact about the meeting place (that it was on a bridge) and uses their lack of response to this "new" information to confirm his suspicions.
 * There was an episode of The Shield that used this trope very subtly. They mention to a suspect that the victims' clothing was found. When the suspect mentions the burned clothing, the interrogator doesn't react at all, and if you're not watching very closely you won't even know why she has a contented look on her face after the interview. Unlike most instances of this trope, the detectives don't gloat to the suspect or do anything else to let the audience in on what's going on.
 * In the Doctor Who serial The Keys of Marinus, Susan is kidnapped and her captor forces her to speak to Barbara over a futuristic alien phone. Later, the kidnapper accidentally lets it slip in conversation that she is aware they have spoken to Susan, even though it was not mentioned. This allows Barbara to realize her guilt.
 * Used again in The Time Meddler when the Meddling Monk (who is holding the Doctor prisoner) claims that he hasn't seen the Doctor but gives himself away by knowing what the Doctor looks like without Steven having told him.
 * In The Daleks' Master Plan, the Doctor realizes that Daxtar is a traitor because he knows that the Daleks' doomsday device requires a core of taranium even though the Doctor never mentioned it.
 * The League of Gentlemen, end of first episode in the Local Shop: just as a policeman investigating a missing person is about to leave the shop and go on his way, Tubbs blurts out "We didn't burn him!"
 * An episode of General Hospital had the cops interrogating a man found driving a missing woman's stolen car (He had carjacked her and left her on the side of the road, but had otherwise left her unharmed). The man tries to claim that he found the car abandoned and denies having ever seen the woman, but when the cops accuse him of foul play, he angrily declares, "I would never hurt a pregnant lady!" The cops had never told him that that the woman was pregnant.
 * In the Stargate SG-1 episode "Window of Opportunity", several planets, including Earth, are trapped in a Stable Time Loop, but only O'Neill and Teal'c are aware of what's happening. During one of the cycles, they arrive to the planet that has an Ancient device that causes the loop and meet an archaeologist O'Neill remembers from the first cycle. The man mentions Carter by name, causing O'Neill to notice that he didn't introduce her this time around, which means that the archaeologist is perfectly aware of the loop and is the one causing it.
 * Debra Morgan from Dexter realizes who really  when the perpetrator asks her what it was like to  . This was far from common knowledge even in the station. She does consider that the person could have figured it out or been told by another cop, and investigates accordingly, but eventually concedes that there is no other explanation.
 * This is how Castle and Beckett identify Beckett's mother's killer. A man suspected of hiring the same contract killer is trying to cut a deal for full immunity from all charges, by insisting it's the only way she'll ever find the guy who killed her mother. Beckett later realizes that she never told the suspect which of her parents was murdered, and that he is the contract killer.
 * On Psych, when the killer of the week is told that he was identified by a witness.
 * On Psych, when the killer of the week is told that he was identified by a witness.

Lassiter: Hang on a minute! I don't believe anyone said the witness' name. You're under arrest."

"Juliet: Do you have an alibi?
 * An earlier example from Season 2, Episode 9 (Bounty Hunters) when Shawn and Gus identify the killer:


 * I don't need an alibi, I'm not guilty.

Juliet: Oh, well, that's okay. 'Cause we can just look at the security cameras from the parking garage.


 * There were no cameras in that parking gara..."


 * Home and Away had a guest character accidentally incriminate herself by identifying a fishing knife as a murder weapon. The police just called it a knife.
 * In an episode of Warehouse 13, an agent is discovered murdered under strange circumstances, and the team tracks down his old girlfriend to ask her some questions, during which she asks whether there have been any more electrocutions. Later, they realize nobody ever mentioned he was killed by electrocution. (Turns out she was also a Warehouse agent, who ran off when her boyfriend was killed during an investigation, and knows exactly what did it.)
 * In an episode of The Pretender, only the actual killer of a young girl knew : There were no pictures in the news of the crime.
 * In the I Carly special iPsycho, Gibby, coming to rescue his friends from Nora, an Ax Crazy Fan Girl who kidnapped them, he asks her if she's holding his friends here. She replies there's no one in her basement, confirming Gibby's hunch that they'd been kidnapped, as he then points out by saying that he never mentioned her basement.
 * Subverted in Terra Nova: after a false confession is revealed to be false despite knowing specific details of a crime, Shannon and Washington realize the actual guilty party made sure that the details were spread around to the colonists to cover any potential slip-ups he might make.
 * Played straight in an episode of JAG when the team were investigating a failed assassination attempt. Told that the would-be assassin had named him as being behind the plot, the perp protested that it was ridiculous to accept the word of a woman who had been subjected to lengthy police questioning. Of course, nobody had mentioned that the assassin was female...
 * A literal interpritation of the trope occurs in the Alfred Hitchcock Presents episode "Road Hog".
 * In an episode of Covert Affairs, Annie is looking for a mole in a training academy, and realizes that one of the trainees was out buying illegitimate booze the night of a leak. She asked why that night, he said he knew he could sneak out because everyone would be busy dealing with another trainee who'd just been cut from the program. None of the other trainees knew she'd been cut until the next morning. (Circumstantial, except when she mentioned that, he attacked her.)
 * An episode of the new Hawaii Five-O had the kidnapper of some college students ask for a woman who'd hid from them during the initial kidnapping, by name, be the one to deliver the money. When asked later how he knew she was in on it, Steve points out her name had never been published in the media to protect her identity.
 * Murder She Wrote featured this often. One episode had Jessica Fletcher tell a group of suspects the murder weapon was found and the killer was identified because he later referred to it as a pizza cutter.

Mythology

 * The Cranes of Ibycus is a classic example of this trope making it Older Than Feudalism. According to a legend first recorded in the 2nd century BCE, the ancient Greek poet Ibycus was murdered by bandits on his way to Isthmian Games. Only the Cranes flying above witnessed the murder. Later the criminals gave themselves away by pointing out 'The Cranes of Ibycus' to one another in public.

Radio
"Pip Bin: The body was covered in hundreds of tiny stab-wounds?
 * A "Five Minute Mystery" titled The Return of Mr. Lawrence plays it by the book: a murdered woman's maid accuses the woman's former husband of poisoning her. The police never said it was poison.
 * Parodied in Season 3, Episode 1 of Bleak Expectations:

Inspector Whackwallop: Aha! I never said the body was covered in hundreds of tiny stab-wounds!

Ripley: Actually, you did.

Whackwallop: Did I? Damn, that normally works. Aha! I never said he was an apprentice carpenter!

Pip Bin: And nor did I.

Whackwallop: Damn."


 * In NPR's radio adaptation of Star Wars, Leia's rebel allies inform her of the Death Star's existence. Later, she's being told about the weapon by an Imperial officer, and accidentally slips the weapon's name even though the officer hadn't mentioned it. Things get ugly from there.

Theater
"Angel: Have compassion, Benny just lost his cat.
 * In David Mamet's Glengarry Glen Ross, blows it by admitting he knew Williamson had, something no one but Williamson and the person who  would have known.
 * From Rent:

Benny: My dog, but I appreciate that.

Angel: My cat had a fall, and I went through Hell.

Benny: It's like losing a -- how did you know she fell?

Collins: CHAMPAGNE!?"

Video Games
"Courier: Can you help me find some missing people?
 * The Ace Attorney games use this a lot. One example in the third game has the murderer give himself away by . This includes Fridge Logic though, since the villain who gave himself away COULD HAVE KNOWN that piece of information..
 * It's actually very unlikely he could have discovered it while he was, as   Even if it did
 * This trope is also Inverted Trope a couple of times - in Apollo Justice, a killer This only causes problems for the villain because
 * That particular villain has a habit of waxing poetic about minor details... which comes back to bite him in the ass twice during that case. Kind of strange given how chillingly cunning he's seen to be otherwise.
 * In the first case of Investigations 2, De Killer refers to the victim by his full name during a cross-examination, while up until then Edgeworth had only ever refered to him by surname. (and, in fact, didn't even know his first name until that point)
 * During the first big plot twist of Chrono Cross,  Needless to say, it seemed like a bad choice of words for Lynx.
 * In Persona 4, reveals himself by saying that he thought everyone was sure that " put them in [the television]" -- no one but the murderer and the protagonists could have known that that was how the victims were killed. He had also cast suspicion on himself in an earlier instance when the protagonists
 * In Mass Effect, when Saren is facing accusations of attacking a human colony and killing another Spectre, Nihlus, he addresses Shepard as "the one who let the beacon get destroyed." Shepard can respond using this trope, saying the only way he could have known that is if he was there. However, Saren quickly rebuffs him/her, saying that Nihlus' files transferred to him upon his death. Unfortunately there is a bit of Fridge Logic here, as Nihlus would not have been able to put anything about the beacon being destroyed in his files because he was dead.
 * Files actually mean "Cases" IRL. If Saren got Nihlus' case, he would have all the info that went with it - what Nihlus wrote down himself and whatever was pertinent to add after his death. Since Saren and Nihlus were associates, Saren would certainly receive info on the circumstances on Nihlus' death - including the destruction of the beacon. Plus, a number of hours pass between the mission and Anderson formally accusing Saren, giving him plenty of time to look things over.
 * In Indigo Prophecy, taking too long to answer Detective Tyler can lead Lucas to blurt out one of these leading to an instant arrest and game over.
 * In Professor Layton and The Diabolical Box, is revealed when he looks at a photograph of the Elysian Box and mentions.
 * In Professor Layton and The Last Specter, a surprisingly spoiler-free AND murder-free version of this is when Layton and co. are looking for some medals with certain parts of raven on them. One of the kids you confront says "We don't know anything about a medal with a raven's tail on it!" To which Layton replies "I never said anything about a tail."
 * In LA Noire, the DLC case "A Slip of the Tongue" features one of these. If Phelps and Bekowski manage to catch up to Jean Archer, they'll mention Belasco (another suspect, ). She later drops his full name "James Belasco", which confirms to Phelps that she's connected to the case.
 * A kidnapping suspect in Kara no Shoujo admits that he has some relation to the person witnessed actually taking the person away before the name of the person is revealed. Woops.
 * In Fallout New Vegas, an exchange something like this takes place during one quest:

Slave trader: I don't know anything about the refugees going missing from the Aerotech Office Park."


 * Used in one of the in-game skill books in The Elder Scrolls series (it levels up your Alchemy). The author of the book recounts a dinner party where everyone (including the author) is spying on the host. After the soup course is brought out, the host declares that all spies in his household have been poisoned, and the antidote is in the soup. Everyone tries to hold out, but one eventually gives in and frantically drinks the soup.
 * Baten Kaitos Origins uses the "innocent character taking the fall" variation. When Juwar is asked for more details of what he did in the city of Mintaka as the Mourning Mistral, he tells Sagi that he planted the bomb in a nearby building after the election speeches...not knowing that the real Mourning Mistral broke their pattern of targeting buildings to target an airpod instead.

Visual Novels

 * is outed as the one who had been bullying Rizu in A Profile because when confronted with a little evidence blurted out the location the evidence had been found in.

Web Comics

 * Whoopsy spleeny!

Web Original

 * In it one chapter of New York Magician, Michel confronts a suspect in a girl's disappearance. Every word out of the man's mouth somehow gets him into more trouble.
 * In one Shadow Unit episode, the gamma, whose manifestation involves causing real bullet wounds with a broken, unloaded gun, gives herself away by being the only person to have heard a gunshot at the death of her latest victim.

Western Animation
"Lawyer: Will you tell the court your whereabouts at the time of the carjacking?
 * The Simpsons (as always) spoofed it:

Willie: I was alone in me Unabomber-style shack; I had nothing to do with that carjacking.

Lawyer: Carjacking?! Who said anything about a carjacking?

[galley and jury murmurs]

Willie: But, didn't you just say--?

Lawyer: I'll ask the questions here, Carjacker Willie!"

"Krusty as a jester: Now we would like to warn you, our performances tend to make audience members blurt out hidden secrets.
 * Another instance in a Simpsons adaptation of Hamlet. Prince Hamlet (Bart) is trying to get his uncle Claudius (Moe) confess that he killed King Hamlet (Homer):

Moe/Claudius (nervous): Oh, boy...

Krusty: Okay, we're going to up open it up with a little improv. Somebody shout out a location.

Bart/Hamlet: This castle!

Krusty: Okay, how about an occupation?

Bart/Hamlet: Usurper of the throne!

Moe/Claudius: [tugs at his collar nervously]

Krusty: I think I heard usurper of the throne. Now, finally I need an object.

Bart/Hamlet: Ear poison!

Moe/Claudius (nervously to Gertrude/Marge): Do you have diarrhea? I have diarrhea... [tries to leave]

[Sideshow Mel, Krusty and the Monkey begin acting out a situation in which Mel starts pouring ear poison down Krusty's ear]

Moe/Claudius: Wait a minute, I didn’t use that much poison!

[Everyone gasps]

Moe/Claudius: I mean, I didn't use that much poi, son, at the royal luau. Hehheh."

"Moe/Claudius: J'ai pas mis autant de poison!
 * Or, in the French Canadian dub:

[Everyone gasps]

Moe/Claudius: J'veux dire, j'aime le miso de poisson. C'est un plat japonais. (I like fish miso. It's a japanese meal.)"

"Clone: No! Sir! I'm telling you, I did not-
 * Beavis and Butt-Head went on trial for throwing eggs at Mr. Anderson's house. They were almost set to be pronounced not guilty when the plaintiff's lawyer noted that Butt-Head had called them "rotten eggs" instead of just "eggs." How did they know they were rotten? They could only stammer, and within a minute the jury pronounced them guilty. (Can you blame the jurors?)
 * Averted in Teen Titans Trouble in Tokyo. A girl who works for the villain approaches Beast Boy and calls him "otaku." Beast Boy takes it to mean that she thinks he's cute, when it actually means "comic book geek", which is something only someone who had been watching him could have known about.
 * He was moping around outside a closed comic book factory. One would assume someone moping on the steps of DC or Marvel's printing plants would be declared a comic book geek too. Though it really doesn't matter, as Beast Boy couldn't understand it anyway.
 * Fillmore: Fillmore is discussing a case with an old friend who's one of the witnesses, and he mentions that 4000 counterfeit baseball cards are still missing. She tells him not to worry, because "it's not like four thousand Cal Ripken cards are gonna just disappear." Fillmore realizes that she must have the cards, because he never told her what player was on them.
 * Batman Beyond: Terry visits Willy Watt in Juvie hall, whom he suspects is the "ghost" terrorizing his high school with telekinetic pranks. During their conversation, Willy brings up the school incidents, even though he's had no visitors or callers since having been locked up (and presumably the incidents never made the news).
 * Star Wars the Clone Wars: In the episode "The Hidden Enemy" one of the clones betrays his brothers. Captain Rex and Commander Cody discover a listening device planted in their command center, and begin to question a squad of suspected clones about it. The turncoat mentions the Jedi had left - something only Rex and Cody knew at the time. Though strangely enough, he wasn't one of the suspects.


 * It's okay, you don't have to say anything till the Jedi come back and talk to you.

...

Cody: What did you mean, "'til the Jedi come back?" How did you know the Jedi were gone?


 * I really wish you hadn't noticed that, Sir..."


 * Spoofed in the American Dad! episode "Black Mystery Month". A detective quizzes Steve at the scene of a murder and is instantly suspicious when Steve mentions details that are clearly visible at the scene.

Real Life

 * This is the reason why newspaper reports about homicides tend to be deliberately vague: The police withhold crucial information until they have had a chance of interrogating the suspects and catch them in these situations.
 * Suspicion that Wallace Souza had ordered or co-ordinated Brazilian gangland murders for his TV show Canal Livre grew when he approached a still-smouldering body in a forest, saying “It smells like a barbecue,” he says. “It is a man. It has the smell of burning meat. The impression is that it was in the early hours . . . it was an execution.”, even though the police had never given a time of death. Also, he tended to arrive a little too quickly at the scene of the crime. He died before he could be prosecuted.
 * As seen on the Saying Too Much page, where a woman was arrested as a suspect in the murder of a man that had won the jackpot and had disappeared, then turned up dead several days later. She was also under suspicion of embezzling it, and after being released from a round of questioning tearfully professed that she had been falsely accused of shooting another human being. Police had yet to release exactly how the man had died.