Recorded Audio Alibi

"A fair cop!" said he. "But, I say, what about that bloomin’ fiddle! I hear it yet."
"Tut, tut!" Holmes answered. "You are perfectly right. Let it play! These modern gramophones are a remarkable invention."

— Sherlock Holmes, "The Adventure of the Mazarin Stone"

Sometimes a character will need to sneak out without letting anyone else know that they have gone. One way of convincing others that they are still where they are supposed to be is to leave behind an audio recording of them doing something (talking, snoring, playing a musical instrument, etc.) so it sounds like they are still there.

This tends to only work if no one bothers to check on them visually, although clever characters can sometimes work around this. Other issues can arise if the recording goes on far longer than the activity logically should, thereby raising suspicions, or if they are gone so long that the recording runs out.

More comedic works may apply The Tape Knew You Would Say That.

Subtrope of Fake Alibi. Overlaps with Fooled by the Sound when it successfully deceives someone. Compare Camera Spoofing and Sleeping Dummy.

As a trope frequently used in Mystery Fiction, examples will be unspoiled. You have been warned.

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Examples:

Anime & Manga

• Case Closed: One perp-of-the-week used this to build her murderer alibi... which Kogoro actually manages to suss out on his own, because he used the same trick to cover up his bar crawls from his wife.

Comic Books

• In the Tintin adventure The Castafiore Emerald, Tintin, scouting the countryside one day in search of the lost emerald, spots Wagner, Castafiore's pianist, heading into town by bicycle. However, the scales he practices endlessly for Castafiore are still emanating from Marlinspike Hall, which becomes less mysterious to Tintin when he and Snowy discover a ladder hidden underneath the window of the piano room and a running tape recorder on top of the piano. When Wagner returns, he is surprised to find Tintin having climbed into the piano room before him, and then surprised again by Castafiore, who opens the unlocked door and scolds him about practicing his scales. Tintin tells her that he's still playing them as the scales continue to issue from the tape recorder, and Castafiore fails her spot check and leaves satisfied with what she can hear.

Film — Live-Action

• In The Case of the Bloody Iris, Professor Isaacs uses a tape recording of him playing the violin to make it appear he is still in his apartment when he is actually out committing the murders.
• In Ferris Bueller's Day Off, Ferris rigs up a recording of himself snoring as part of his elaborate Sleeping Dummy, with the recording triggered if anyone opens the bedroom door to look in. He also sets up a prerecorded message to trigger when the doorbell is rung to trick outsiders into thinking he's sick in bed. Rooney catches on that Bueller isn't home the second time he rings the doorbell.
• Home Alone:
  • In Home Alone, Kevin uses the audio from a mobster movie to trick a pizza boy into leaving the pizza at the door.
  • In Home Alone 2: Lost in New York, He uses an audio recording of him peeping on his uncle in the shower along with a blow-up novelty doll to trick hotel staff into thinking that his father is in the hotel room with him when he's actually there by himself. He also repeats the same trick from the first movie with another mobster movie in order to cover his escape from hotel staff.
• In The Ladykillers (1955), the gang pretend to be a group of musicians, and play music on a gramophone to allay the suspicions of their landlady.
• In Live and Let Die, The Big Bad Dr. Kananga enters the San Monique consulate in New York and starts dictating a long-winded speech. A short way in, he switches on a tape recorder that continues the speech from where he left off. He and his entourage change into street clothes and exit through a Secret Passage, while the agents monitoring his office continue to listen to the speech; unaware that he has left.

Literature

• The Murder of Roger Ackroyd has a variation. After killing Ackroyd Dr Sheppard jury-rigs a Dictaphone to an alarm clock to loudly play Ackroyd's voice later to make it seem like Ackroyd is still alive. He then uses a Phoney Call to get summoned to the scene, "discover" the body, and walk out with the Dictaphone in his doctor's bag.
• In Mystery on Southampton Water by Freeman Wills Crofts, one of the conspirators records his half of a conversation on a gramophone. While he is committing his crime, his accomplice goes into the room where the man is supposed to be, plays the recording, and speaks his half of the conversation, thus making it seem to the witnesses outside that both men are there. Inspector French considers this to be a "very old trick" (the book was published in 1934).
• Sherlock Holmes: "The Adventure of the Mazarin Stone" contains what is probably the Ur-Example and Trope Maker. Holmes offers the villainous Count Negretto Sylvius and his helper, boxer Sam Merton, freedom if they give up the eponymous jewel, or jail if not. He invites them to discuss the deal while he plays violin in the next room. When the Count decides to double-cross Holmes and takes the stone from his secret pocket to show Sam in window light, the detective springs from the chair in place of his replica and grabs the £100K jewel. His bedroom has a gramophone and secret passage to behind the curtain.

Live-Action TV

• Columbo: In the episode "Double Exposure" subliminal advertising expert Dr. Keppel hosts a screening where he shows a film to the businessmen who commissioned it. Since they may wish to revise the script later the film has no audio and is instead narrated live by Dr Keppel. At least, it seems like he's narrating it, but midway through he switches to a tape he made ahead of time so he can sneak off without anyone noticing.
• Death in Paradise: In the two-part "Music to My Ears"/"Fake or Fortune", the Victim of the Week is a concert pianist who would sneak out of his house without anyone knowing by going into his music room to practice, putting one of his CDs on repeat, and then sneaking out the back.
• Doctor Who: Forms part of Bennet's illusion in "The Rescue". Pretending to be unable to walk, he spends most of his time "resting" in his chambers. When he sneaks out to don his Koquillion disguise, he leaves behind a taped recording of his voice rigged to tell anyone who tries to enter to "go away."
• Good Luck Charlie: "Baby's First Vacation" sees Teddy fake being sick so that she doesn't have to go on vacation with her family and can instead throw a party. To sell the illusion she claims to have set up a webcam so her mother can check in, then films a video with Ivy to make it look like she's sick. However, as the video is only fifteen minutes long Amy begins to get suspicious after prolonged watching prolonged.
• iCarly: In "iLook Alike, Carly and her friends want to watch an MMA match, but Spencer refuses to let them go. They decide to use their look-alikes that they met earlier in the episode and come up with a recording of 20 different responses they could use. Unfortunately, when Spencer comes up to talk to them, they fumble the responses and he catches on as soon as he sees their faces.
• Midsomer Murders: In "Till Death Do Us Part", the murderer hosts a popular radio show in which they establish a false alibi by airing a prerecorded episode during the murder.
• Monk: In "Mr. Monk and the TV Star", actor Brad Terry uses an old recording of his ex-wife screaming in a horror movie she had appeared in to make it seem like he was being interviewed by paparazzi at the exact moment she was being attacked.
• In one episode of Murder, She Wrote, the murder is hatched by two rival doctors who hate the victim even more than each other. They use a tape-recorder to stage a blazing row in a closed office while one of them slips out to do the deed. Jessica demonstrates the scheme by walking up behind a group of hospital staff who think they're listening to her arguing with the police detective in the same office.
• Only Murders in the Building: In Season 1, on the night of Tim Kono's murder, Jan's signature instrument (her bassoon) is heard playing across the courtyard of the Arconia, as she does with Charles later. She establishes that she practices nightly. But, on the night of Tim's murder, it was a recording to cover up the fact she killed him.
• Poker Face: In the episode "The Stall", Taffy and Mandy's plan to stage George's suicide involves Taffy pre-recording a long-winded diatribe about hot links, which buys him enough time to do the deed.
• The Suite Life of Zack & Cody: Parodied. Following being grounded by their mother in "Doin' Time in Suite 2330" Zack and Cody sneak out through the vents, leaving behind taped recording of them playing "Go Fish" on loop to convince her their still in their room. Said taped recording is only a few seconds long and thus amounts to same sentences being repeated over and over again for hours. Despite this, it completely fools their mother.
• Veronica Mars: Mercer lies to Veronica and tells her that he couldn't be the Hearst College rapist because he runs a radio show that goes out at the same time, which clashes with several of the rapes. When Veronica hears Mercer's show skipping, she realizes that he lied to her about her show being live and it's actually pre-recorded - and then he's immediately revealed to be one Hearst College rapist.
• Whodunnit? (UK): A variant is used in "The Q43 Experiment". The murderer kills the Victim of the Week while he is recording his lab notes on a tape recorder: ensuring that the murder is Caught on Tape. The killer—who is confined to a wheelchair—plays a recording of high-heeled shoes walking away, giving the impression that the killer is able-bodied and female. They slip up, however, and there are more footsteps than it would take to reach the door.
• Young Dracula: Van Helsing does it in "Halloscream"; going into the bathroom and leaving behind a tape of himself whistling to convince Jono that he is still in there while he stages a Bathroom Break-Out.

Video Game

• Nancy Drew: In the "The Final Scene", Nancy realizes Joseph is the culprit when she stumbles upon a recording of the sound check he supposedly did when Maya was kidnapped.

Visual Novels

• Phoenix Wright: Ace Attorney – Dual Destinies: Professor Means is supposed to hold a public speech, but needs to step out for crimes. So he plays a recorded speech. It's caught because he mentions a statue that's been changed without his knowledge, and Athena notices that the fake death threat had white noise on it that was the same length of the speech.
• Phoenix Wright: Ace Attorney – Trials and Tribulations: Luke Atmey uses a captured surveillance photo of himself as Mask☆DeMasque stealing the Kurain Sacred Urn to establish an alibi for the murder of Kane Bullard. It turns out that the photo was actually taken days in advance and the time stamp was manipulated by Atmey, who was responsible for setting up the security measures at the museum.

Western Animation

• Futurama: In "T: The Terrestial", Bender accidentally leaves Fry behind on Omnicron Persei 8. Feeling guilty for his actions, Bender uses an audio recording of Fry and some creative use of the fast-forward and rewind button on an answering machine to deceive the others into thinking he's still on Earth. It actually manages to trick everyone, with Fry even managing to become Employee of the Month.
  Bender: Hang on, Fry! I'm a-comin' to save you! (plays with tape)
  Recording: You – are – my – her – o.
  Bender: Shut up, Fry, I know it!
• Miraculous Ladybug: Adrien Agreste sometimes plays recordings of classical piano music to make it seem like he's practicing the piano, thus allowing him to sneak out as Chat Noir.
• Used for a brief gag in Spongebob Squarepants episode "Pressure", where Spongebob readies a record-player in the second Sandy takes her eyes off him to give himself a head-start in their impromptu race ("I'm already halfway there... Halfway there... Halfway there...!")
• Totally Spies!: A variation is used by Tim Scam to sell his ruse that Jerry had retired in "The New Jerry", each time they tried to call him they received a short video of Jerry playing golf, claiming he couldn't help them as he was retired and then hanging up. Which this initially fools them, after watching several times the girls realise the video is exactly the same each time and thus it's fake.

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