Interdisciplinary Sleuth

"To be a real policeman Be big and strong by heck But let the strength be always found Just above the neck."

- Courtesy is the Best Policy, a tribute to the Newfoundland Ranger Force

This character is an expert, trained in some field where crime-fighting is not a usual goal. They however use this expertise to catch criminals, probably alongside a more conventional Detective Drama hero (i.e., a police officer or private investigator).

A subtrope of Amateur Sleuth. Compare Superhero and The Exotic Detective. Contrast Mundane Utility. See also Mystery Fiction.

Comic Books

 * During her time with The Fantastic Four, She Hulk investigated a photographer who was taking pics of her sunbathing on the Baxter Building by helicopter. At one point she commented, "Well, I'm a lawyer, which makes me 25% detective."

Literature

 * Father Brown; the title character uses his priestly knowledge of human evil—acquired mainly from hearing confessions—to help him solve crimes.
 * Brother Cadfael is a monk and apothecary.
 * In at least one of the Lord Peter Wimsey mysteries, "The Bone of Contention," Lord Peter's hobby of bibliophily helps him gather evidence.
 * Harry Dresden of The Dresden Files is a wizard -- mixes up magic potions, summons demons, makes deals with faeries -- in a setting where most people don't believe magic is real; he works as a freelance consultant for, among other things, the police, on cases with an occult or supernatural element.
 * Surviving the Applewhites has an In-Universe example --Debbie Applewhite writes a series of books about a florist who solves mysteries.
 * Sano Ichiro, an honorable Samurai who happens to be very good at solving mysteries.

Live Action TV

 * Much of the cast of Bones. Brennan and Hodgins are both academics by training; Angela is an artist.
 * Charlie Eppes of Numb3rs solves crimes with mathematics.
 * This at least is far more plausible then some variations of this trope. The Real Life FBI probably uses mathematicians too.
 * Rick Castle of Castle solves crimes with Genre Savvy, being a mystery writer.
 * Cal Lightman in Lie to Me solves crimes with body language psychology.
 * Patrick Jane in The Mentalist.
 * Shawn Spencer in Psych doesn't really qualify, but his partner Gus's day job as a pharmaceutical rep occasionally helps solve the Mystery of the Week.
 * Dr. Sloan of Diagnosis: Murder uses his medical knowledge to solve crimes.
 * Jonathan Creek, an excellent inventor of magic tricks and an excellent detective.
 * The Magician. Anthony Blake (Bill Bixby) uses his stage magician skills to solve crimes and help people.
 * Andy Barker, PI: divides his time between Murder Mysteries, his wife, and his main job: Certified Public Accountant.
 * On The X-Files, Scully started out as a doctor before she switched tracks to the FBI. Fanon has Mulder starting out as a psychologist before a similar career shift.
 * Leverage and White Collar both feature thieves that use their skills to solve crimes. However the crew of Leverage generally commits crimes in the process while Neal is a consultant for the FBI. Also the villains of Leverage usually are in a position where normaml law enforcement is unable to help.
 * In NCIS, only DiNozzo and Kate are from a law-enforcement background, him a cop, her a Secret Service agent. Gibbs is a former Marine sniper, McGee's got degrees in computer science from MIT and biomedical engineering from Johns Hopkins...and Ziva's an ex-Mossad assassin. Their respective backgrounds come up more often than you'd think.

Web Original

 * In the browser game Sleuth, you play a Private Detective, and you have the option of choosing a preset background for them. Some of the backgrounds (for example a doctor whose medical license was revoked by political enemies) aren't strictly law enforcement or detective types.

Real Life

 * The FBI generally recruits people with skills outside law enforcement and trains them as opposed to taking trained former local officers.