Lisa Lutz is a private person. She doesn’t keep a diary—because they’re admissible in court—and she has an interesting privacy pact with a friend.

“If I die, she needs to get hold of my computers and delete everything,” Lutz says, speaking from a motel room in Niagara Falls, N.Y. (More about that later.) Then she adds, quickly, “Not that there’s anything incriminating.”

This all makes sense for a person who writes about secrets and how they inform a character’s behavior. “Everyone is their facade,” she says. “And then the rest of them is all hidden. I’m fascinated by that.”

These skeletons in the cupboard also drive the plot of Lutz’s thrillers and comic crime novels. Her first, 2007’s The Spellman Files, is about a family of private investigators who also spy on each other. She originally wrote it as a screenplay, but after it didn’t sell, she decided to turn it into a novel.

The Spellman Files launched a bestselling series that today numbers six books and has been called spirited, outrageous, hip, and hilarious, and it’s also been optioned for film several times, most recently by Fox Entertainment, according to Lutz’s longtime agent, Stephanie Rostan at Levine Greenberg Rostan Literary Agency. (Take that, Hollywood.)

Lutz’s latest novel, The Accomplice (Ballantine, Jan. 2022), centers on the 16-year friendship of Luna Grey and Owen Mann, and the women who love Owen and end up dead.

“Luna and Owen grabbed me immediately,” says the book’s editor, Kara Cesare. “In particular, their intense, flawed friendship and how dangerous it was to be in their orbit.”

Unlike the Spellman series, The Accomplice isn’t overtly funny. But the dialogue is witty and the characters are quirky: one fakes a seizure and another hoards ferrets, “wearing” them on an ugly Christmas sweater. They’re also brazen enough to push a depressed friend into a pond on a freezing winter morning in the hopes of snapping him out of his funk. And Lutz is excellent at making the reader suspicious of just about every character in the book.

The Accomplice opens with Luna and Owen meeting in an intro to ethics class in college. Shortly afterward, Luna, who has epilepsy, has a seizure while sharing her notes with Owen. They are alone, and he cushions her head with his jacket and sticks his fingers in her mouth in the belief that epileptics are at risk of swallowing their tongues—a fallacy for which she later ridicules him. The cement for their bond is set, despite the fact that their personalities are different: Luna is guarded, sometimes flippant and mysterious, whereas Owen is affable, popular, and privileged.

The book alternates between Owen and Luna’s college days, during which time Owen’s ex-girlfriend is found dead, and the present, when, early in the book, Owen’s wife meets the same fate. Luna finds her body and runs to tell Owen before calling the police. Things look fishy.

The pages turn quickly as the reader follows these suspicious but beguiling characters and their dysfunctional families. Lutz, however, says she didn’t feel confident about the book as she was finishing it. In fact, she worried it was garbage.

“I thought people were going to make fun of me,” she recalls. But when she gave it to a few trusted readers, the overall response, she notes, was, “Oh, this is so much better than the others!”

Lutz is funny, self-deprecating, sweet, and a little mysterious during our FaceTime interview. She is staying in a motel on the U.S. side of Niagara Falls during a stopover on her cross-country drive back home to Upstate New York. She might be selling her house and moving back to Seattle, but she doesn’t want to elaborate. “It’s complicated,” she says.

A novelist and screenwriter with girl-next-door bright eyes, clear skin, and high cheekbones, Lutz, 51, grew up in Southern California. After high school, she took courses at UC Santa Cruz, UC Irvine, University of Leeds in England, and San Francisco State University. Despite all those stints at different schools, she never got a college degree and wasn’t formally schooled as a writer.

“I don’t know if I would have done well in that kind of environment,” Lutz says, adding that, when it comes to fiction, universities tend to celebrate the writing more than the story. “It might have been helpful, but I think it’s also limiting. I think the reason I’ve done well is a certain freedom I’ve given myself. For me, there are no rules if you can get someone to turn the page.”

In her 20s Lutz did a series of odd jobs, including one working for a family of private investigators. The job gave her the idea for The Spellman Files. But before that she wrote and sold a screenplay titled Plan B, a mob comedy made into a film released in 2001 starring Diane Keaton. The movie bombed and Lutz’s subsequent screenplays didn’t sell.

So what inspired her to think she could turn a screenplay that failed to sell into a novel that would?

“I had office jobs that were soul crushing,” Lutz says, adding that she was so determined to make her living as a writer that she didn’t give herself other career options.

Asked when, precisely, she decided it would be writing or bust, Lutz recounts an experience from her undergrad years: “A friend in college was making a short film. I read his script and thought, I can do that.” And she did. The result, she says, was “terrible and, in retrospect, embarrassingly weird.” Nonetheless, the experience sparked something. “I don’t think I ever stopped actively trying to be a working writer from that point on.”

Lutz left San Francisco, where she moved after she dropped out of college, and holed up alone in a relative’s empty house in Upstate New York to write The Spellman Files. Rostan read it in late 2005 and sold it in 2006.

The early Spellman novels were bestsellers and, according to Rostan, the series has sold more than 750,000 copies worldwide. Lutz’s standalone fiction has also performed; Rostan points to 2016’s The Passenger, Lutz’s ninth book and third standalone, which she says has sold more than 300,000 copies to date.

“Lisa has a very strong voice,” Cesare says. “I always tell her I’d read a grocery list of hers and find it interesting, because she is so unique in how she approaches everything she writes.”

And Lutz can produce: The Accomplice is her 12th published book in 14 years. Asked about the secret sauce to being so prolific, she responds that writing genre novels involves a workmanlike approach for her—when she’s ready to start, she shows up and continues to write until she figures out the story. And she usually shoots for 1,000 words per day, which takes her about three hours, first thing in the morning. She writes a first draft pretty quickly but says she sometimes has to throw away 100 pages of the result.

“That can hurt,” she admits. “I try not to do that now.”

With The Accomplice, Lutz knew the central crime’s ending before she started. But the idea she had for Owen and Luna’s friendship turned out to be totally different from what she originally had in mind.

Lutz says she tries to have fun when she’s writing and wants to feel free, mentally. She’s also happiest when she feels like something happens in the story that’s “nuts.”

“When I have a crazy idea that still works,” she says, “that’s bliss.”

Renée Bacher is a freelance writer whose work has appeared in the New York Times Magazine and the Washington Post Magazine.