Mistaken Confession

"Detective Krevoy: [trying to control himself] This wasn't your first time, was it, Ted? How many we talking?

Ted: Hitchhikers? I don't know - twenty-five... fifty maybe - who keeps track? Hey, I know this is the Bible Belt, but where I come from this is not that big a deal."

- There's Something About Mary [Detective Krevoy is talking about murder. Ted is talking about giving hitchhikers a ride.]

Someone confesses to something that wasn't actually what the interrogators were asking about. Often happens after a bit of Perp Sweating.

Often the conversation will play out so that none of the dialogue between the cops and the Mistaken for Murderer lets slip that he is really talking about the cookie he stole from his mother's house (which has been plaguing him ever since).

Compare You Just Told Me and One Dialogue, Two Conversations. Subtrope of Poor Communication Kills.

Comic Books

 * In the Tintin book Flight 714, the millionaire Laszlo Carreidas is kidnapped and injected with a truth serum in an attempt to force him to reveal the details of his Swiss Bank Account. But instead of revealing the relevant details, Carreidas engages in boastful rants about his underhanded exploits, much to the annoyance of his captors. Hilarity Ensues when Rastapopoulos, the mastermind behind Carreidas' capture, is accidentally injected with the serum in a struggle.

Film
"Mortimer: Certainly, there are thirteen bodies buried in the cellar. And I've got hundreds more up in the attic, Captain!"
 * Played for laughs in The Goonies. When the Fratellis catch Chunk and order him to tell everything under threat of shredding his arm in a blender, he proceeds to tell them every bad thing he's done in his life.
 * Famously played for laughs in ~There's Something About Mary~ where Ted confesses to picking up a hitchhiker when he's actually under arrest for murder.
 * In My Cousin Vinny, the protagonists are arrested after realizing they accidentally took a can of tuna from a store without paying for it. In reality, the shopkeeper had been murdered shortly after they left, and witnesses reported seeing a car like theirs leaving the store. So, they confess to what think is just a shoplifting charge, and are shocked when they realize it's a murder charge.
 * Part of the problem is that when one of the defendants realizes the charge against him, he incredulously repeats "I shot the clerk?" several times in an attempt to clarify.
 * In L.A. Confidential, where suspects for a mass homicide in a diner actually confess to kidnapping and gang rape.
 * Appeared in a black-and-white Sherlock Holmes film when Watson accused a man of murder only to find he'd stolen a teapot.
 * In the play/film Arsenic and Old Lace, Jonathan thinks he's caught by the police when the police really just caught another policeman who forgot to check in.
 * Not to mention Mortimer's aunts casually confessing to their serial murders in front of the police chief despite his frantic attempts throughout the movie to keep them from being discovered. Fortunately, they've just signed papers committing themselves to a mental institution so he manages to convince the police not to believe them.


 * In Presumed Innocent, as DA Sabich is point-blank accused of killing his colleague/ex-lover by another colleague, he angrily snaps at him, "Yeah, you're right. You're always right!" Following his arrest, his colleague declares his intent to testify at the trial, claiming that Sabich confessed to the crime. Fortunately the judge realizes that Sabich was no doubt being facetious and blasts the other lawyer for his deliberate failure to realize that.

Literature

 * Happens in a novel called The Futurist.
 * In The Brothers Karamazov, Dmitri confesses "I killed him" to the constables there to arrest him for murdering his father when he thinks he murdered Grigory the butler. Happens all throughout the interrogation as well, when Dmitri says one thing and the cops interpret it against him.
 * In the play The Miser by french author Moliere, the eponymous miser, Harpagon, accuses his servant Valere of stealing his stash of money. Valere thinks he is talking about his daughter promising to marry Valere. This misunderstanding goes on as Valere talks about the beautiful eyes of Harpagon's 'treasure'...
 * Invoked by Tyrion Lannister when he is accused of attempting to murder a seven-year-old boy, Bran Stark, and murdering Lord Jon Arryn by his insane widow, Lysa Arryn. He loudly gives a public confession of his numerous "crimes," including lying on numerous occasions, whoring, insulting the queen (his sister) and her father, and so on. This was a ploy to call Lysa out in public about her behavior towards him and demanding a trial, which she was honor-bound to give.

Live Action Television

 * Played straight on the CSI-Without a Trace crossover, in a bit of an Idiot Plot moment.
 * 3rd Rock from the Sun had an episode where Dick confessed to being gay, but thought he was confessing to being an alien. Hilarity Ensued.
 * Happened the other way around in Buffy the Vampire Slayer episode "Phases" - Xander thought Larry was confessing to being a werewolf, when in fact he was just coming out of the closet.
 * Happened the normal way in the same conversation. Xander had previously been possessed by a hyena spirit, so knew a little what it would be like to be a werewolf. His little speech on the subject made Larry think that Xander was coming out the closet, and that encouraged Larry to.
 * In Buffy the Vampire Slayer Willow literally sweats a confession out of Jonathan, using a desk lamp, but it turns out instead of killing the swim team bullies, he just pissed in their pool.
 * Pretty much every episode of Frasier ever.
 * The Colonel does one of these in the Doctor Who episode "The Unicorn and the Wasp",
 * In The Office accountant webisodes, the accountants asked Phillis if she had spent any company money on something, hoping to find the missing $3000, she admits to having bought something with a company card, but it was a heel for her shoe, only costing $14.
 * The Wire features a drug dealer named Cheese being caught talking about killing "my dog" on the phone, and the cops listening in on it through their wiretap are stunned that he's freely discussing killing a friend. Turns out he really was talking about his dog, who he had to kill after it was injured in a dog fight, and the cops have just advertised that they have a wiretap up over this.
 * One episode of Castle, they catch up to a murder suspect, and the first thing she says is: "I did it. I did it, I did it." (She was admitting merely to taking a bribe to put the victim on that particular jury.)
 * In a different episode, one suspect  confesses to Beckett's face that he's "dying to cop a feel under her cop blouse."
 * On one of the very few episodes of the short-lived sitcom Go Fish, a high school teacher thinks his student is on drugs, while the student is under the impression that the teacher thinks he's gay. In a hilarious instance of a confession being mistaken by both parties, the entire affair is resolved when the student explains, "I'm straight."

Video Games
"C. Montgomery Burns, I know you're guilty! J'accuse!...Sir.
 * In the first level of The Simpsons Hit and Run, Homer accuses Mr Burns of being behind the mysterious black vans all over town.

Fine, I admit it, I had Amelia Earhart's plane shot down. That hussie was getting too big for her jumpers."

Western Animation
"Pinkie Pie: NO! You're not understanding me! I want you to confess!
 * The character Wade did this regularly in the U.S. Acres segment of Garfield and Friends. In one episode the farm's cow had been stolen. Wade was questioned, and within minutes, he confessed to, among other things: wearing wax lips out of season, putting lettuce and tomato on a corn beef sandwich, eating all of a piece of bread but the crust, and phoning information for numbers he could have looked up himself. However, he didn't even mention the missing cow.
 * In The Simpsons, Lisa tries to get Jessica Lovejoy to confess to stealing the church's collection money, so she stands in front of the congregation and asks that the criminal confess now. As she didn't specify which crime she was referring to, everyone in town starts owning up to random things. And when Jessica plays dumb through the entire thing, Lisa just says "Oh what the heck...IT WAS JESSICA LOVEJOY!"
 * There's also the episode where Bart believes Flanders killed his wife after overhearing him saying "I've killed her... I'm a mur-diddly-urdler!" Turns out he just killed a ficus plant.
 * My Little Pony Friendship Is Magic: Pinkie decides to interrogate Spike to find out why her friends are ignoring her...

Spike: I'm the one who spilled juice all over Twilight's copy of Magical Mysteries and Practical Potions! *wince*

Pinkie Pie: And?

Spike: And I'm the one who used up all the hot water in Ponyville yesterday when I took a seven-hour bubblebath! *harder wince*

Pinkie Pie: AND?

Spike: ...And sometimes, when no one's around, I do this... *flexes arms in front of mirror* Lookin' good, Spike! Lookin' REAL good!

Pinkie Pie: *Eye Take*"


 * Doug once accidentally turned in a doodle he made of Mrs. Wingo along with his homework assignment, and was panicking as she began grading each of the papers. Doug decided to try and act casual and maybe she would never find out he made the drawing. But as soon as she asked who turned in something, before she could finish the sentence, Doug confessed, only to find out she was asking who had turned in a paper titled "My First Pair of High Heels".