Emma Donoghue knows how to put people in their place. In Room, her 2010 mega-bestseller, she held characters and readers captive in an 11-by-11-foot space that constituted an entire world before releasing five-year-old Jack and his saintly Ma to society, wounded but resilient. Readers of Room emerged too, with ragged fingernails and bleary eyes, the signs of a tense all-nighter.

In her new novel Frog Music, Donoghue keeps her narrative grip tight while flexing new muscles, leaving the confines of Room for the steamy, seamy streets of 1870’s San Francisco. Based on the unsolved murder of a wise-cracking, cross-dressing frog catcher named Jenny Bonnet, Donoghue’s latest book combines the fast-paced formula of a crime novel with the immersive style of historical fiction she offered in earlier novels like Slammerkin.

“I’m constantly looking out for odd historical incidents,” says Donoghue, who came across the story of Bonnet’s murder 15 years ago while reading a book about Victorian women. Donoghue began preliminary research on Frog Music long before she started writing Room (“snatching time in libraries when I had a few hours to use the microfilm reader”), so she didn’t suffer the tyranny of the blank screen that plagues some authors after the publication of their bestsellers. “I write in an overlapping way,” says Donoghue, “so on my computer now there are plans and notes for the next four or five books. By the time I got around to writing Frog Music, I thought, ‘At last, here I am! I finally get to write about this!’ ”

Though Jenny Bonnet wasn’t famous, her story captured Donoghue’s imagination. “Jenny Bonnet struck me as the right person to get shot through a window in that she was such a ‘seize the day’ kind of 27-year old. The spark of her character seemed to cross the centuries, and I got really intrigued about how she died.”

With a lengthy police record and a devil-may-care attitude, Jenny lived a bohemian life, riding her fancy bicycle through the hills, catching frogs to sell to restaurants, and sleeping wherever she could find a bed or a patch of grass. (Bonnet’s character may remind readers of another gender-bending, street-smart loner of more modern literary fame, Lisbeth Salander.) When Jenny befriends a feisty French burlesque dancer and prostitute named Blanche Beunon, their fates are intertwined. On the night Jenny is murdered, the two women are hiding out in a saloon on the outskirts of town. Beunon vows to find the perpetrator and bring him to justice. (She has more than one reason to suspect her jealous French pimp, the father of her missing baby boy.) Over the next three days, Blanche ventures through whorehouses, Chinatown tenements, and baby “farms” to piece together the crime. San Francisco, ravaged by smallpox and a historic heat-wave, is cinematic but sinister in Donoghue’s depiction, proving that prison doesn’t always take the form of an 11x11 foot room.

Donoghue found that the 1870s were fascinating years in San Francisco’s history, as the city struggled to reconcile the boomtown legacy of the Gold Rush with a more buttoned-up sophistication. “It was a time when the respectable people of the city were trying to impose some kind of order, to make it more like Philadelphia,” says Donoghue. “But it still had this fundamental wildness. San Francisco has always been pulled in two ways—there are the people making the money and the people who have no money at all, just living off the sunshine.”

Most of the characters in Frog Music fall into the latter category, which made research a  daunting task. “The sources for this book weren’t as full as they would have been if I’d been writing about the rich and famous,” says Donoghue, “but they led me on to hidden sectors of society.”

Not that there weren’t any sources on Jenny Bonnet’s murder. As Donoghue dug through newspaper files, she found close to 60 different articles about the case. But the victim’s relative obscurity and the general slipperiness of journalism in that era kept the author digging deeper into source material, which helped fill in the biographical gaps.

“I do the majority of research up front, but as I’m writing, my work constantly throws up other questions that send me off for more research,” says Donoghue. “What you can’t do is intimidate yourself. You can’t think ‘Oh, I must know everything there is to know before I write this book.’ In a way, it’s only in drafting the scenes that you find out what it is you really need to know.”

While Donoghue is no stranger to writing historical fiction, writing a crime novel was a new challenge. “I don’t think a literary novelist can throw a murder in there and think they’re writing crime,” she says. “Crime is its own literary tradition and it’s a very powerful genre. The rules of the genre offer such satisfaction to the reader, that I didn’t want to do it in a causal way.”

Donoghue believes murder mysteries and literary novels are not irreconcilable, citing Donna Tartt’s books. “In the best murder mysteries, there’s always more to it than just solving the crime. I definitely want to offer the satisfaction of who pulled the trigger, but you want to leave the reader struggling and wrestling with the moral issues as well.”

Despite the recent publication of Frog Music, Donoghue has already moved on to other projects. She is an executive producer of the film Room. “It’s my first experience with film and I’m really enjoying it so far,” she says. “Reworking the story with a more visual angle is fascinating. It’s thrilling to think that the movie will reach a whole new population—because you know there are people who don’t read books, shocking though it is!”

Donoghue is also writing a children’s book for eight-to-12-year-olds. “As a genre, it’s more terrifying to me than detective fiction,” she says. “Again, a literary fiction writer who writes for adults doesn’t necessarily have the skills to write for kids. But it’s very important to keep challenging myself because otherwise writing could get too comfortable. I want each new book to be like a gun to my head saying, ‘Come on, can you manage this? Can you rise to this?’”

Donoghue can see the advantage of sticking with one genre, but for her it has no appeal. “Each book wouldn’t seem so scary, but it would be harder to write because you’d be coasting,” she says, reaching for another metaphor. “Just like falling in love, it’s all about chemistry. You’ve got to be excited or the sentences do not come.”

Kirk Reed Forrester is a freelance writer based in Houston.