I did a search for “computers in detective fiction” and found this site: Technological Mysteries – Mystery Readers International
There’s a lot of resources listed, but the first of the two articles reprinted there seems to be about the type of thing you’re looking for.
Sue Grafton had her detective, Kinsey Millhone doing database searches on behalf of her corporate client (an insurance company) and in her private cases. I don’t think she had a PC on her desk, but had access to terminals and PCs.
“A” is for Alibi was published in 1982. I cant recall if there was computer use in the first book of the series though.
it certainly doesn’t count as famous but the T.V. show Riptide from 1984-1986 dealt with a group of detectives, one of whom was the stereotypical computer geek. I think they used an Apple ][ to help solve crimes. And a helicopter.
This is a stretch, but Matthew Broderick did some detective work in WarGames, hunting down the mysterious game computer that wouldn’t identify itself and then hunting down its creator (although I think he used microfilm for that).
On second thought, maybe disregard. 
The Whiz Kids TV series might be a closer fit.
I remember reading on some site dedicated to old computers that many of the “computers” shown in those 1960s detective shows were not actually computers, but punch card sorting machines. An inside joke among people who actually worked with computers was that they almost always showed the card with the “answer” being spat out the machine’s “reject” slot.
Remember there are several generations of Nancy Drew. The '50s '60s ones don’t have her using any computers, at least until book 60 or so which is as far as I got reading them to my daughter. I’m sure the updated ones do, but they would be way after the other examples given here.
I’d go with Mannix, mentioned before, as using serious computers as opposed to the magic card spitter computer of Batman. I don’t remember the computer output ever being very useful in the first Mannix season, though.
The Venice Police Dept. admin in Donna Leon’s Brunetti series is not just a computer user but a hacker, and she has friends who can get all sorts of information. Brunetti himself gets more comfortable with PCs as the series progresses, but Signorina Elettra is the expert.
There were some episodes of Magnum P.I. that revolved around Mac (and later Maggie) using the Navy computers to help Magnum with this and that.
One in particular (Computer Date, from 1982) involved an employee of a large company doing some sort of computer espionage, and the CEO hires Magnum to also while he’s at it find out if his wife is having an affair, and she was…with Rick!
There was an old movie of the week (well, it’d have to be old if it’s a “movie of the week”) that involved a mainframe computer. A bunch of college kids working in the “data processing department” on campus create a fictional person using the computer to give him a real life background and paper trail. Somebody discovers what they did and takes over the fake person to cover his own misdeeds. Once he starts killing off the kids they have to figure out who the baddie is. I think they used the computer to narrow down the search. This would have been in the 70s?
Found it: https://www.imdb.com/title/tt0067551/
I’d expect one of the SF writers to be the first. While it may be that Conan Doyle talked about fingerprints when they were still speculative, I don’t know that mystery authors tend to have their fingers on the cutting edge of technological innovations in the world. And the majority of fiction, of any genre, is pretty “paint by numbers” so I would expect that many of the guys who were devoted to futurology would take their personal interest (be it robots or flying cars or whatever else) and write a by-the-numbers adventure novel about it, a military novel, a noir detective novel, etc. to churn out the pages and earn their next check. There are only so many sci-fi ideas and so many plots in the world, yet you have to keep producing content if you want to put food on the table. Whether you want to or not, you need to fill every box in the table where you have SF on the rows and plot on the columns.
So whoever was getting all fanboyish about computers early on would likely have the first detective novel to include them.
I haven’t read the book but this does sound like a pretty fancy mystery story:
Isaac Asimov, 1958
Wonder what you’ll think of Linda Barnes’ sleuth Carlotta Carlyle in her 1995 novel Hardware, especially this discussion of how computers are bound to change the sleuthing game. Or this description of hacking in the next Carlyle book Cold Case?
I think a case could be made for the Carlotta Carlyle series (1987-2008) as a transitional form of the computer-gimmick detective, including the introduction of the computer-whiz sidekick character. This essay describes the transition more comprehensively:
Thanks, this looks promising. It also looks like it’s more science fiction-oriented, until you get down to the computer-able sidekicks, but this might be paydirt!
“Multivac” sounds more like that disembodied voice from “City on the Edge of Forever,” but I haven’t read it either, so maybe!
Yeah, I’d be surprised if Nancy didn’t have at least an iPad Mini in that shoulder purse of hers these days, but she’s notable in this presentation for something else, and I suspect some other gumshoe beat her to the punch on this one.
These sound great! And the quote at the end mentions Sara Paretsky, reinforcing the possibility that V.I. Warshawski is who I’m looking for.
Good! And I just noticed that the allusion to “Harris” in that last-linked article is referencing Snowboarder Bo’s earlier cite. (And 1995 sure seems to have been a tipping-point year for this phenomenon.)
It’s the year a lot of people got online for the first time, including me. I think it’s when America Online crossed some momentous threshold, like 10 million subscribers or something. The internet had been around in some for m or another since 1969, but this was the year the average person was as likely as not to be online and have a computer at home.
Came out in 1982, though.
Deckard’s order “Enhance” as he was looking at Leon’s high-res photograph was nicely parodied in Super Troopers.
Multivac was a magical mechanical god sort of computer, not a “realistic” one.
The earliest “realistic” depiction of the Internet is usually regarded as being Leister’s “A Logic Named Joe”, but while it’s in a sense a mystery, it’s a very trivial one:
The story’s equivalent of Google (which the main character names “Joe”) has a glitch that results in it answering all questions, including ones like how to transmute cheap metals into valuable ones, and how to get away with murder. The protagonist realizes how much trouble this will cause, and so sets out to track down the glitching hardware. Which he does in the obvious way: He asks it where it is.
There was a kid-detective book (along the lines of Encyclopedia Brown) I read when I was young, with a computer whiz who used his programming skills to solve various cases, and each chapter was followed by the source code for the real program he used (so, definitely real-world computer use). I think it might have been Chip Mitchell and the Case of the Chocolate-Covered Bugs, but even if that wasn’t it, it appears to be along the same lines. And it was published in 1985.