Bluffing the Murderer

Our Hero is certain she knows who committed the crime. Unfortunately, she doesn't have much evidence, so she maneuvers the criminal into panicking in a way that's likely to be self-incriminating.

Some variants include:
 * 1) Police announce they will be making a search of a particular area. The killer feels forced to remove some weak evidence from the place first. The police actually already had that evidence, and now they have the strong evidence that the killer knew about it and tried to conceal it.
 * 2) Tricking a criminal into revealing the location of a key piece of evidence (such as a body). One unlikely version is that the police forge some evidence to make it seem the victim's been seen around; killer goes to check on the place where the body is hidden; cops follow him there. Allegedly Truth in Television: police used a clever ruse to get the murderer of John and Phoebe Harries to reveal the location of the body.
 * 3) The most dangerous kind: a character is put into a position where they're dangerous to the murderer's schemes. A common way of doing this is trying to blackmail the murderer. In any case, when the murderer attempts to kill this new obstacle, the police burst out from hiding and the murderer is caught red handed. (Though for a new crime)

This trope is particularly common in armchair detective fiction, where the hero often has only determined the culprit through a long chain of interlocking deductions and subtle observations which would never hold up in court.

Compare Engineered Public Confession (which plays off the villain's overconfidence rather than their panic), Perp Sweating, Framing the Guilty Party. Will occasionally result in I Never Said It Was Poison. Often a supertrope of You Just Told Me.

Anime & Manga

 * In Death Note L tricks Light with one of the aforementioned variants very early on. Light usually reacts coolly as part of his acting skills later on. Of course, this being Death Note this happens something along the lines of every episode, and is probably one of the most common Xanatos Gambits used.
 * Detective Conan sees plenty use of this trope. A particularly good example is from the first Case Closed movie, in which Conan tells the suspect that he found the disguise he used while conducting his bombings. (He actually made it himself out of stuff he found in the room.) The bluff succeeds and the suspect says "But I left those in the study." Oops.
 * Parodied in Yuria 100 Shiki. A boy who's recently watched a show called Bolumco discovers a close-up photo of a vagina on his father's hard drive. He has no idea what it's a photo of, so he shows it to his friends, and his female friend (who thinks it looks vaguely familiar,like she's seen it from a different angle) shows it to her foster father. He immediately denies all knowledge of what it is, so the boys bluff him and pretend they've figured out its location—and of course, he immediately looks in the direction of the girl's crotch.
 * One of Kindaichi's favorite tactics is to put the suspect in a position where they'll be killed by their own death trap unless they take action (and thus implicating themselves, since an innocent person wouldn't know about the trap).

Comic Books

 * In the graphic novel Camelot 3000, Merlin has been betrayed by one of the reincarnated Round Table knights. King Arthur orders the suspects to hold Excalibur and attest to their innocence, claiming his sword will magically strike down anyone who lies while holding it. The guilty party panics and confesses, after which Arthur admits that Excalibur has no such power.

Film

 * The hero in the French movie Le Bossu uses this to unmask the murderer.
 * The climax of the film A Few Good Men has the defense lawyer provoking the base commander into a rage in the hope that he would admit to ordering the beating that killed the Marine. It's the sequence that the very famous line does not come from. The bluff hinged on the base commander lying about the time of a particular flight. The defense attorney brought in two airmen that he implied were going to testify as to the actual time of the flight. Turns out that the airmen had absolutely no recollection of anything.
 * Bud does the same in an episode of JAG by infuriating the suspect in the murder of a bumbling sailor by putting on a full-on act of Obfuscating Stupidity in the courtroom.
 * He's not a murderer, but Captain Queeg in The Caine Mutiny  falls afoul of this trope during the mutiny trial, when the defense officer provokes him to a complete loss of control on the witness stand, thereby proving that his removal from command was justified.
 * In Star Trek VI, when the murderers of the Klingon Chancellor are themselves found dead on the Enterprise, Kirk and Spock have someone broadcast an order over the ship's P.A. system for a court reporter to report to sickbay to take statements from the two men. Naturally assuming that the men actually survived their assassination and are about to spill the proverbial beans, the assassin,, heads straight to sickbay to finish the job...and finds Kirk and Spock waiting there instead.
 * In the Al Pacino/ Robin Williams film Insomnia, the police find the murder victim's backpack in the woods, and Pacino orders them to replace it and then put out a reward for any information about it, so that the murderer will return to collect it before anyone else finds it. It worked, but he still got away at the time.
 * This comes from the Norwegian original, the same results.
 * In Doubt,

Folklore
"Stephen Fry: I'm going to raise the tone, now. Why did the inventor of the decimal point encourage his servants to stroke his cock?"
 * Supposedly John Napier used this as a tactic to figure out which of his servants had been stealing from him. He covered a rooster in soot and put it into a darkened room, commanding everybody in town to enter the room and touch it, and declaring that the one whose touch caused the rooster to crow is the criminal. One by one, the townspeople enter the room and then leave. The rooster never made a sound. Napier then pointed out that one man had clean hands, showing that he never actually touched the rooster for fear of causing it to crow—proving his guilt.
 * QI discussed the subject in series C:


 * There are lots of old variations on this, such as a judge who hands out "magic sticks" to everyone in the village and tells them that the thief's stick will grow an inch in the night. The thief is the one who returns his stick with the end sawn off.

Literature

 * Perry Mason. He always does this, and he always does it in the courtroom, when the murderer is on the witness stand. (Which may be why that variation is known here as The Perry Mason Method). 32 movies (at least!), 245 television episodes, 11 years of radio shows, and 80 novels and short stories worth of Bluffing the Murderer.
 * Which gets confusing when said murderer is a fan of Mason and it still works. You'd think that, when he got called to the stand, he'd just confess and save everyone some time.
 * In Feet of Clay, Vimes confronts and hints that he's being surrounded by, in a way that should only makes sense to  if he was behind the plot to kill Vetinari with.
 * Another Discworld example; in Men At Arms, Carrot spreads a rumour that they have  in custody so that the villain goes to the place where they found   corpse.
 * Yet another, in Night Watch, Vimes uses the ginger beer trick on two of the Cable Street Particulars in order to get the third to talk.
 * In Memory by Lois McMaster Bujold, Miles bluffs  into trying to swap out an incriminating air filter.
 * Subverted partly in that Miles was bluffing with a real test—had the killer not moved the incriminating air filter, it would have been found in his private office. It did help his case enormously to catch the perp with the attempted evidence tampering red-handed than merely making him a strong suspect, as more than one person could have been in that office.
 * It was a bluff because he didn't have enough solution to test every air filter on the floor, but he pretended to be methodically testing all of them to avoid giving his suspicions away.
 * But Miles was prioritizing by places where Illyan spent most of his time, which included the killer's office, so he would have gotten there before he ran out of his test solution. (And it wasn't like he couldn't have more made. For all the killer knew he'd left a bunch of lab techs busy downstairs whipping up another batch.)
 * Poirot did this once when confronting the real ABC killer, by stating his fingerprints were found on a typewriter he sent to his scapegoat. He did it another time, with fingerprints on a bottle of poison, to which the killer replies "It's impossible! I was wearing--" Oops.
 * This is a common tactic of Encyclopedia Brown.
 * In the Lord Peter Wimsey novel Strong Poison, Lord Peter eventually gets the murderer to confess in part by pretending to feed him arsenic-laced food; the murderer had committed the crime by becoming immune to arsenic and sharing a poisoned meal with the victim.
 * In the Brother Cadfael novel A Morbid Taste for Bones by Ellis Peters, Cadfael makes use of the superstition that a murdered body will bleed more if the murderer touches it by getting the daughter of the murdered man to ask the suspect to place a crucifix over his heart.
 * The Sherlock Holmes stories have a number of examples.
 * Sherlock pulls one of these in The Valley of Fear. Deducing that some vital evidence has been dumped in the moat, he announces that it must be drained - then catches the murderer  when they come to move the goods. Pure bluff, in that it was impossible to actually drain the moat.
 * He pulls a type 3 on Colonel Moran in "The Adventure of the Empty House". He knows Moran was Moriarty's Dragon, and he also knows that Moran was responsible for a high-profile murder case. He's in danger as long as Moran is free, so he uses a wax replica of his head to trick Moran into shooting him. The police (who were alerted by Holmes) burst into the titular house where the Colonel was hiding and arrest him after he reveals himself.
 * In one of Jill Paton Walsh's detective novels the police inspector states that they almost never get enough evidence to perfectly unambiguously convince the jury and win a trial, instead they get enough evidence to convince the murderer that they could, at which point they confess.
 * In Arrow's Fall, the third of Mercedes Lackey's original Heralds of Valdemar trilogy, Herald Talia and Herald-Princess Elspeth catch a traitorous nobleman this way.
 * Note that a telepathic probe of Talia would have ordinarily been enough to at least detain someone for questioning under the Truth Spell (the only thing that anyone lied about during the staged confrontation was Talia's relative health), but seizing a high ranking and almost completely trusted royal advisor without solid evidence is a delicate matter.
 * Nero Wolfe does this more often than he doesn't.
 * This is how Elijah Baley solves the case of roboticide in Isaac Asimov's The Robots of Dawn, getting . He does the same in a more cruel way in The Naked Sun.
 * Porfiry of Crime and Punishment tries this many times on Raskolnikov. One particular instance involves Porfiry directly asking Raskolnikov about a detail at the crime scene when Raskalnikov is talking about his presence at the scene before the murder.
 * Hannibal Lecter bluffs himself into this position by attacking Will Graham in a very self-incriminating way—little did Lecter know Graham had no real evidence on him, and knew he was the Chesapeake Ripper only because his own Lecter-level intuitive imagination led him to the conclusion.
 * Jules Verne's Keraban the Inflexible has the same trick as Napier uses (explained below in the Folklore session), except with a goat instead of a rooster.

Live-Action TV

 * This is basically Columbo's modus operandi. More than half the episodes have him pulling this one, a few times even involving tricking the murderer into trying to kill him.
 * Law and Order: Criminal Intent does this a lot. One good example was the Season 2 finale, where Goren manages to pin a murder meant to discredit him on Nicole Wallace through a complicated routine involving anthrax samples and her supposed immunity.
 * Another variant came when they realized that their initial suspect was being framed by her husband. Since both were lawyers, they couldn't inform the ADA without both the wife and the culprit finding out. This results in the detectives lying to the wife, the real suspect, and the Assistant District Attorney in charge of the case in order to obtain a confession. They've done that last bit twice, and on at least one occasion he wasn't to happy about it.
 * In fact, the second time he said that if they did it to him again, he would make sure they didn't have a badge by the end of the day. Goren and Eames were actually quite surprised.
 * In yet another Criminal Intent episode, a hitman/family man who kept the bodies in a giant freezer in the garage (under the ice cream!) was undone after Goren convinced the medical examiner to report that one of the people who was murdered had lost a cap from his tooth. The hitman tore his garage apart all night trying to find it, and in the morning, when the cops came around, he blurted out how he hadn't made a mistake, there was no cap, and they arrested him.
 * The original Law and Order pulled a similar gambit on a woman they suspected of hiring a hitman to kill her husband. They discovered a crucial piece of evidence (a jailhouse informant) after they had rested their case. In the US criminal justice system the prosecution is not allowed to introduce new evidence on rebuttal unless it undermines something in the defense, and the defendant cannot be forced to testify. So they made up a cock-and-bull story, claiming that the wife killed the hitman out of revenge (which they knew to be false) and which the defendant could have only refuted by testifying. The attorney puts his client on the stand to defend against the false charge, giving McCoy the opening to introduce his informant to prove the real one.
 * In Full House, Jesse's cousin from Greece came to visit. He was a model citizen in front of Jesse, but he was a deviant, from trying to seduce Jesse's girlfriend, to rigging a charity drive that would actually fund his trip to Disney Land, among other things. Becky, Jesse's girlfriend, ends up trying this to get Jesse to believe his cousin is a dirtbag. It fails, but it's the thought that counts.
 * The "White Bird" episode of Knight Rider has the hero confront the villain with vague threats. If the villain would just sit tight, keep his cool and not panic, he would have gotten away; however, he panics and phones his henchman, setting his own downfall into motion.
 * Probably more episodes of Knight Rider than just this have employed the trope.
 * Monk has done this in several episodes, including "Mr. Monk and the Panic Room" and "Mr. Monk Goes Back to School".
 * Also inverted in the episode Mr. Monk Meets the Godfather, where Monk actually did think the FBI Van parked nearby recorded the killer's confession, but it turns out they hadn't because Monk inadvertently wrecked the bug (he had the tie washed in a washing machine due to a stain earlier in the episode), although the killer did end up begging to be arrested anyways, namely because he didn't want the mafia to commit revenge against him.
 * Practically the central plot device in many episodes of The Pretender, where the main protagonist coerces a confession out of each villain of the week by threatening to subject them to the very same horrifying fate they had previously subjected their victims. While the approach certainly satisfies a sense of poetic justice, this editor has to wonder how any confession obtained by stranding the accused on top of a (albeit fake) toe-popper mine could possibly hold up to scrutiny in a court of law.
 * While Jarod was never particularly concerned with the legality of the confessions, he did have a few things going for him. First, he wasn't a member of a law enforcement agency, so it could be argued that the suspect was not being interrogated by a government agency (fruitlessly). Second, he only bluffed the murderer when he had evidence, or used it to collect evidence, so the confession was more for his satisfaction than for legal use. And third, sometimes he was able to convince the perp to voluntarily surrender and confess to the actual police by promising to do far worse if he/she didn't, which, while ambiguous in terms of legality, gives the police an untainted confession. Sort of.
 * If a given Murder, She Wrote episode doesn't end with this, it'll end with Engineered Public Confession. Most often, it's both: Jessica tricks the murderer into returning to the scene, confronts him/her alone, and then the police turn out to be hiding in the wardrobe after s/he confesses.
 * Employed numerous times in CSI. In one example, the investigators determine that the victim's company-issued travel bag is missing and was probably taken by the murderer, but are unable to obtain a search warrant... so they obtain an identical bag from the company, hide a tape recorder in it, and bring it into their suspect's interview. The suspect immediately gives himself away by protesting that they must have searched his car without a warrant.
 * Babylon 5: Although not quite a murderer, the.
 * Dutch tries this all the time on The Shield, with varying degrees of success. Claudette is also pretty good at it, but her moment also comes back to bite her in the ass. She gets a confession out of a serial killer by fooling him into thinking that his sister is dead, and that they will convict him for that crime. He returns the next season, representing himself, and manages to raise enough doubt about Claudette's credibility to get the DA to drop the death penalty. (He was going to spin the Bluff as a hallucination caused by her Lupus medication).
 * Silent Witness. While investigating a murder in Zambia, Nikki Alexander convinces a group of villagers that she is using witchcraft to "speak to the bones" of a murdered woman. First she describes the victim (information obtained from the post-mortem) then she gets the villagers to lay their machettes in front of them. When flies are attracted to the invisible blood droplets on the machette used by the killer, she picks it up and declares that the spirits have told her the owner is the killer. He promptly flees in panic and is grabbed by the police.
 * In Mash, Hawkeye unveils a thief by tricking him with this sort of ploy. He tells a group of people that the last object stolen had been treated with a substance that would turn the thief's fingers green. When one of the people tried to hide his hands, Hawkeye knew he was the thief.
 * The Closer had a variation on this. They left two criminals handcuffed in a police car outside their house while the team searched it. By listening in on their conversation the team not only got the confession they were looking for, they also found all sorts of incriminating evidence.
 * The Mentalist features this a few times.
 * In one episode of Bones, they suspect that a guy helped his friend with the murder, but don't have enough proof. Instead, Bones bluffs that his friend ratted out on him and when he demands for her to say something his friend would say, she calmly tells him that his friend made a comment that he had difficulty putting on the sleeve on the corpse, proven by the corpse's broken arm. At that point, the guy promptly told her everything in order to get back at his friend.
 * Done unintentionally in Cold Case. The team has a witness to a crime scene where his mother was killed. They call in a woman whom the witness recognized. As soon as they mention there's a witness saying she helped with the murder, she quickly denies it, claiming it was impossible for anyone to see that night.
 * Not surprisingly, done several times in Castle. Some notable instances:
 * Beckett/Castle and Esposito/Ryan are investigating different murders, which they determine are related in a Strangers on a Train scenario. While interrogating the suspects separately, Beckett/Castle rush into Esposito/Ryan's interrogation room to announce that their suspect confessed first, prompting the second suspect to immediately confess everything and blame the first guy (who hadn't confessed to anything.)
 * Castle gets his own in a Crowning Moment of Awesome: a stuck-up rich kid has killed his girlfriend's ex-boyfriend, framed his friends for the murder, and is convinced that Beckett has no proof (he's almost correct—it's slim). Castle launches into an extended, sinister-sounding "he had it coming" routine on behalf of the killer, who responds with "Exactly."
 * The IMF use this technique frequently, particularly in Syndicate-related episodes of the later seasons. Sometimes the target is led to believe there is incriminating evidence, such as a recording or film, which he obtains (aided by the team of course) and, upon realizing that it's patently inaccurate, actually incriminates himself by pointing out the inaccuracies that only the perpetrator would know about.
 * The "place all the suspects together near the murderer's hidden time bomb, forcing the murderer (as the only one who knows about the bomb) to reveal himself in order to save his own life" variant was used twice on the 1954 Sherlock Holmes TV series—once with actual explosives and once with arsenic candles.

Theater

 * In Hamlet, this is the entire point of The Murder of Gonzago (the play within the play).
 * Subverted brutally in Dame Christie's The Mousetrap. All the witnesses/suspects are asked to to re-enact the murder, but to do so playing the part of one of the other witnesses. It seems an exceedingly clever ploy (or a bold bluff) to effectively catch the murderer, who...
 * In Arsenic and Old Lace, the hero Mortimer tries to bluff his Ax Crazy brother Jonathan into leaving by threatening to introduce the cops to his latest murder victim. Subverted when Jonathan then threatens to tell the cops about the murders his kindly old aunts have committed, and then doubly subverted when Mortimer arranges to have his aunts committed to a mental institution and Jonathan.
 * The entire plot of Rehearsal For Murder is one of these... sort of.

Videogames

 * In Ace Attorney, it could be argued that the player character does this in every single case. When the evidence is overwhelmingly against their client, they manage to use the existing evidence to find the real killer. Some examples:
 * Phoenix Wright gets the crook caught by using this in the third case of Trials and Tribulations.
 * In case 3-1, Mia Fey (the attorney the player controls in that case) proposes the theory that the real killer The killer then goes on to break down and refuse to take some, therefore proving Mia's theory.
 * Something like this happens in the first case of Apollo Justice, where
 * Nine Hours Nine Persons Nine Doors:
 * The Elder Scrolls games have an in-game short story, A Game at Dinner, which uses a lethal varient of this:

Western Animation

 * Duckman does this to humorous effect in thwarting one of King Chicken's plots. After Cornfed gets him exonerated of all the charges, Duckman then calls King Chicken to the stand and proceeds to "interrogate" him by rambling senselessly until a fed-up King Chicken finally confesses just to shut him up.

Real Life

 * The 2009 Shafia family murders in Kingston Mills, on the Rideau Canal in Ontario, Canada: A vehicle was found in the canal with four corpses inside; the Kingston Police Department, secretly sceptical of the family's claim that one of the victims negligently drove into the canal herself, invited them back to Kingston on a pretext. While they were inside the police station, cops secretly bugged their minivan. They then took the family on a tour of the locks, where they'd installed a decoy camera. They recorded panicked conversations as the suspects drove home. “They’re lying. If there was a camera they’d access it in a minute,” the husband said, his second wife replying “There was no camera over there. I looked around, there wasn’t any. If, God forbid, God forbid, there was one in that little room, all three of us would have been recorded.” Much of what they said was incriminating, ging 705 Division one more piece of a puzzle they'd ultimately complete (with backup from three other police forces) to send all three to prison for life for murdering their own family.