Dashiell Hammett was a Pinkerton detective. James Ellroy became obsessed with the Black Dahlia murder after his own mother’s violent death. Jim Thompson’s father was an Oklahoma sheriff who fled the state under a cloud of scandal—and eventually settled in Fort Worth, Tex., where his teenage son supplied guests with drugs, bootleg liquor, and prostitutes as a bellhop at the Hotel Texas.

It’s hard to match the origin stories of America’s hardboiled crime novelists, but Jordan Harper’s comes close. Speaking over Zoom from his home in L.A.’s Eagle Rock neighborhood—the Edgar Award for his first novel, 2017’s She Rides Shotgun, perched on the fireplace mantle behind him—Harper traces his interest in crime fiction all the way back to 1932, when a pair of car-thieving brothers holed up in a farmhouse near Springfield, Mo., and then opened fire on the policemen who’d come to arrest them for murdering a local deputy. Six more cops—including Harper’s great-granduncle—were killed in the Young Brothers Massacre, one of the deadliest incidents in U.S. law enforcement history.

When Harper was a boy, his grandfather—a prison guard who loved Johnny Cash, made knives in his spare time, and remembered Bonnie and Clyde passing through Springfield—gave him a copy of a 1930s police booklet about the massacre. “It was very pulpy and very violent,” Harper recalls. “It uses all caps when the gun fires, the wound ‘sizzles’ as the bullet passes through, all that. Somebody gave me this when I was really young and told me it was very important. And I really absorbed a lot of that.”

After college, Harper stumbled into a brief career as the music critic for a St. Louis alt weekly (he remembers attending one of Nelly’s birthday parties on a riverboat casino) before “aging out” of the job and moving to New York City. Around the same time, his grandfather and Johnny Cash both died, inspiring Harper to write a short story in which an old prison guard avenges his granddaughter after her rapist is set free.

Harper eventually found a home for “Johnny Cash Is Dead” and other stories in Todd Robinson’s influential online magazine Thuglit, and published a story collection, Love and Other Wounds, with Ecco in 2015. By then he had been living in L.A. for seven years. A spec script for The Shield (“Still my favorite TV show of all time,” Harper says) landed him a spot in the Warner Bros. Writers Workshop; from there, he spent five seasons writing for The Mentalist, which led to work on Gotham, Hightown, and other series.

Though Harper says that being in the writers room for a case-of-the-week mystery show is both “amazing training” and “one of the most fun jobs that I can imagine,” there are also downsides, including “the need to make something that appeals to millions of people, which can lead to a lot of flattening.” As an escape from the “moral universe” of The Mentalist, in which “the victims always had to be sympathetic and justice had to be delivered,” he began writing She Rides Shotgun, the gritty story of an ex-con and his 11-year-old daughter on the run from a white supremacist prison gang.

With his new novel, Everybody Knows (Mulholland, Jan. 2023), Harper has once again managed to turn Hollywood frustrations into top-notch crime fiction. The plot—which follows “black bag publicist” Mae Pruett, whose firm gets paid to hide the rich and famous’s dirtiest secrets, and her ex-boyfriend, disgraced-cop-turned-fixer Chris Tamburro, across an L.A. hellscape dotted with sex predators, crooked cops, and fallen child stars—has its roots in an earlier short story, but the driving force behind it is Harper’s recent experiences adapting and executive producing James Ellroy’s L.A. Confidential for CBS. Though the pilot wasn’t picked up, the process left him with “all this kind of James Ellroy energy locked up inside me and wanting to try and do a big epic L.A. crime story,” he says. “That’s where the very first idea of doing Everybody Knows came from.” (It also gave Harper, whose dog is named Ellroy, a great anecdote about meeting one of his literary heroes: when they were introduced backstage at Hollywood’s Egyptian Theatre and Ellroy learned the pilot was produced by CBS, Harper recalls, “he goes, ‘So you can’t say—’ and then he just let off a string of words that you absolutely cannot say on network TV.”)

Intended to “be in conversation” with landmark L.A. noir novels by Ellroy, Dashiell Hammett, Raymond Chandler, and others, Everybody Knows spurred Harper to think deeply about how he could “level up” as a novelist, he says. To nail down the sprawling plot—which involves a string of arsons at homeless encampments, a controversial real estate development deal in Crenshaw, the shady comings and goings at an influencer “clout house” in Laurel Canyon, and more—he hired a writer’s room assistant to help map out “the backstory of the crime in chronological order from start to finish.” To make sure he was working “in partnership” with his subconscious to give the novel a “purely unique tone,” he created a “spirit board” of 30 or more influences—everything from Ellroy and Megan Abbott (“the best crime writer working today”) to film composer Cliff Martinez and the avant-garde Japanese queer movie Funeral Parade of Roses.

Harper explores the thought process behind these and other literary techniques in his newsletter, Welcome to the Hammer Party, which he admits can get a bit “esoteric.” (Sample nuggets: “Approach everything with a beginner’s mind”; “You ride the tiger, but also, you are the tiger.”) “I’m very interested in talking about storytelling at the most abstract level,” he explains. “I am trying to get down to the absolute essentials, where it would apply as much to an action movie as a kung fu comic book as a romance novel, and asking what are the truths that I believe? A piece of art to me is a sustained and unbroken dream where you open up that book and you fall in face forward, and I think you can do that with anything.”

To build the dream world of Everybody Knows, Harper drew on everything he’s seen and experienced in L.A. and Hollywood over the past 14 years—from the best places to get boat noodles and tacos al pastor to the feeling of “being a cog in this big machine that exploits people and is also exploited by very bad people,” he says.

Recently, though, he had what may be his strangest L.A. experience yet. He was out for a walk when a sobbing woman flagged him down and told him she thought her neighbor was dead. “I don’t know how to give CPR, but maybe I can do something to help somebody,” Harper recalls thinking. “I walk up the steps and I open the door and I look at just his legs—he’s wearing shorts—for 0.25 seconds. And I turn around and I tell the woman, ‘He’s very dead.’ He’s been dead, obviously, for days.”

Harper says that after the incident, he didn’t write for a week. Then he forgot two appointments in one day. “I was like, what’s going on? Oh, yeah. I’m traumatized. And it was bad.” He pauses for a beat. “This is very narcissistic to now pivot to how this aided me as an artist, but it did. I realized I emptied my total L.A. into Everybody Knows. There are so many things in this book that are true stories or rumors that I’ve heard or places I’ve been. What I haven’t done in the last two years is refill that Los Angeles tank. So, the first thing I did is buy a police scanner. I’m going to start nightcrawling.”