A character has a hobby or other leisure activity that actually hides their criminal activity. Often they're genuinely interested in the hobby, which lets them make money from doing what they like and avoid Bluff the Imposter questioning.
Compare Naughty Birdwatching (where astronomy and birdwatching equipment is used for a less noble purpose) and The Convenient Store Next Door (where the location that is used to perform said hobby is an important part of the criminal plan).
- The French comic L'Effaceur (The Eraser) is a comedic series about a hitman and the difficulties of his job. He happens to have a passion for sculpture, so there are several strips where he disposes of a corpse by sinking it in a cement block, then making a statue out of it (it's even one of the contracts he offers). One strip has a customer requesting the victim be turned into enough miniature soldiers for a Napoleon wargame.
- The French comic Les Maitres de l'Orge (The Barleymasters) has Adrien Steenfort, a rich brewer, go for a lone walk every evening without fail with his dinner's leftovers to feed the local cats. In fact, he's going to feed Garcin, his son's murderer (he'd set fire to the brewery, not knowing there were people inside), who he's kept walled up in the ruins of the brewery for twelve years, using him as a captive and silent audience. At the end of the story, Steenfort's been in the hospital for a few days and finds Garcin has starved to death. The loss of his captive confidante (he compares the nightly monologue sessions to an addictive drug), in addition to his financial and family woes, makes Steenfort burn Garcin's body and commit suicide.
- In Runaways, said hobby is philanthropy. The main characters' rich parents are supposedly part of a charity group, but this is a front for their world-ending plan involving Human Sacrifice.
- In the My Little Pony: Friendship Is Magic fic Loved and Lost, Prince Jewelius is early on established to travel a lot in order to explore and learn more about Equestria. After he seizes the throne by using the events of "A Canterlot Wedding" against the heroes (all but Twilight), he privately tells them that his real reason for traveling so much has been searching for the means to usurp the princesses he has secretly hated for years. He learned about the Changelings and the caverns underneath Canterlot through these travels, and once he was told the date of his cousin Cadance's wedding, he traveled to the Badlands to forge an alliance with Queen Chrysalis, providing her information about the caverns where she imprisoned Cadance and Twilight.
- Tangled: Inverted. The pub thugs when the viewer first meets them, seem to be only defined by their being criminals; but once the song "I've Got A Dream" comes, we find out they all have hobbies (playing the piano; baking; mime; interior design; etc.) that they'd really love to turn into their jobs.
- The Ladykillers (2004): The plot begins with Professor Dorr renting out an old lady's basement so he and his friends can practice classical music. In fact, they're digging a tunnel to rob a nearby casino vault, playing recorded music to mask the sounds of their work. While Dorr is Wicked Cultured and likely is a musical enthusiast, the rest of the crew... aren't.
- Played with in Alfred Hitchcock's Psycho. Norman's hobby is taxidermy, which not only establishes him as kind of creepy but also would provide ample reason for him to know how to chemically disinfect things. However, this isn't used as while he does clean the bathroom, it's an efficient scrub. Still, it's implied that after he (and, yes, at this point very mentally ill) grave-robbed his mother's corpse after murdering her, to make her appear as semi-lifelike as she does he may have stuffed her, too. With his mental state surrounding his mother, though, he probably wouldn't know if he did.
Marion: A man should have a hobby.Norman: Well, it's, it's more than a hobby. A hobby's supposed to pass the time, not fill it.Marion: Is your time so empty? [...] Do you go out with friends?
- Played with in The Wrong Arm of the Law. While Nosy Parker immediately suspects that Pearly Gates is still using his fashion boutique as a front for his gang's activities, Pearly insists that the fashion boutique is now a legitimate business that he runs on the side.
- Escape from Alcatraz: As part of their escape plan to dig out the back of their cell, the four prisoners register to obtain recreational tools such as an accordion so they can hide what they're doing from the guards. However, at least one of these hobbies (painting) is instrumental in itself since they need flesh-colored paint to create convincing dummy heads.
- The Great Escape: Colin's the Forger's hobby as a bird watcher provides one of the many means to conceal the prisoners' efforts right under the Germans' noses, by having their forgery workshop time done while he's (supposedly) giving birdwatching lessons.
- Sherlock Holmes:
- The Hound of the Baskervilles: Stapleton is an amateur entomologist, forever going on long expeditions into the moor to hunt butterflies. It's also a good way to go to the abandoned mine where he's keeping the giant hound with which to terrify Sir Baskerville. Holmes tells Watson that Stapleton really is an entomologist, even discovering a new species of moth under one of his previous identities.
- "The Red-Headed League": A pawnbroker's assistant is always taking pictures and running off to the darkened basement to develop them. In fact, he's digging a tunnel to the bank behind the shop.
- Isaac Asimov's "The Mule": Magnifico plays a Visi-Sonor, an instrument that creates visual illusions in addition to sound, very well. Well enough that he's allowed to give concerts on every planet that he, Bayta, and Toran go to. The climax reveals that he's the Big Bad, and the instrument served as an Amplifier Artifact for his Emotion Control powers, allowing him to demoralize the Foundation leaders.
- In The Cat Who Sniffed Glue, an actor murders his identical twin and impersonates him so successfully that no one around them note , including people who'd known them both for years, suspects a switch has taken place. He's only found out when the eponymous cat detects the glue holding his fake mustache on (the dead twin had a real one, which was shaved off at the time of the murder).
- Midsomer Murders: On occasion, the crimes are committed because of the hobby, which are Serious Business in Midsomer and cause for any number of reprehensible activities from adultery to blackmail to creative accounting. One episode has a mentally disturbed woman murder people who might interfere with the local tourist attraction (a miniature village), a Social Climber murders any potential witnesses that saw her driving drunk (which would have barred her from entering the village social club), etc.
- In The Scooby-Doo Show episode "There's a Demon Shark in the Foggy Dark", Mr. Wells stated that cabinetry was his hobby, which enabled him to hide stolen pearls near a frozen shark monster.