Whenever someone asks me to name today’s top suspense novelists, my short list always includes Tana French. French is such a gorgeous writer: She’s a poet of mood and a master builder of plots that are positively Piranesi-like in their ingeniousness. Her Dublin Murder Squad series (which began in 2007 with “In the Woods,” which won the Anthony, Edgar, Macavity and Barry awards) relies on the simple device of a recurring cast of police detectives, although that device isn’t so simple psychologically. Since each novel is told from a different detective’s point of view, we loyal readers come to know the characters inside and out — both in the way they see themselves and in the (often jarring) way others see them. The mysterious depths of human personality are as intriguing to French as are the mysterious deaths that often set her stories in motion.

“The Secret Place,” French’s fifth Dublin Murder Squad novel, pries open the hermetically sealed world of teenagers at a tony girls’ prep school and lets readers peer into the toxic stew of hormones and homicidal rivalries roiling within.

Detective Stephen Moran is the lucky lad selected by fate — in the form of 16-year-old Holly Mackey — to breach the walls of St. Kilda’s School in search of answers to a murder case turned cold. Six years earlier, Holly (whose father is homicide detective Frank Mackey) was a witness in a murder case, and Moran was the cop who interviewed her; now she’s grown into a self-possessed young student at St. Kilda’s.

Holly turns up at the squad room one morning bent on giving Moran a postcard she found posted on a St. Kilda’s bulletin board. Here’s Holly’s explanation and Moran’s eye-rolling commentary:

“ ‘There’s this board. . . . It’s on the top floor, across from the art room. It’s called the Secret Place. If you’ve got a secret, like if you hate your parents or you like a guy or whatever, you can put it on a card and stick it up there.’

“The Secret Place” by Tana French. (Viking)

“No point asking why anyone would want to. Teenage girls: you’ll never understand. I’ve got sisters. I learned to just leave it.”

The postcard Holly brings, however, is more menacing than melodramatic. On it, an anonymous writer has scrawled, “I know who killed him.” The “him” in question is Chris Harper, a hottie from a nearby boys’ school whose flower-strewn corpse was discovered on the grounds of St. Kilda’s the previous year. Eager to make his mark in the elite ranks of the Murder Squad, Moran races the postcard over to Antoinette Conway, the prickly detective in charge of Harper’s stalled murder investigation. In a nonce, the two accidental partners find themselves knocking at the polished door of St. Kilda’s, looking for, at best, an informant; at worst, a killer within.

French is exquisitely sensitive to the look and manner of mean girls: the mocking stares, the whisper campaigns, the delicate skill with which cliques eviscerate the outsider. As it becomes evident that the anonymous tipster must belong to one of two rival cliques, Moran and Conway begin to question those girls. When one of the Queen Bees — a girl named Joanne — enters the room, Moran is taken aback:

“I’d been expecting something impressive, all the hype. Medium height. Medium thin. Medium looks. Hard-work straight blond hair, fake tan, skinny eyebrows. . . . Only the way she stood — hip cocked, chin tucked, eyebrows up — said Impress me. Said The Boss.

“Joanne wanted me to think she was important. No: admit she was important.

“ ‘Joanne,’ I said. Stood up for her. ‘I’m Stephen Moran. Thanks for coming in.’

“My accent. Whirr, went Joanne’s filing system. Spat me out in the bottom drawer. Eyelid-flutter of disdain.”

Author Tana French. (Kyran O'Brien)

There’s a merry, working-class shrug of defiance about those last remarks. Both Moran and Conway hail from the wrong side of the river (as Dubliners say), and Moran, in particular, is thrown off balance by the posh privilege of St. Kilda’s, which he resents and covets. Along with her acute sensitivity to issues of social class, French is always alert to the presence of the supernatural in her tales, whether it be the lingering aura of a pagan past (“In the Woods”) or the haunted emptiness of a contemporary suburb (“Broken Harbor”). Holly and her friends regularly escape the confines of St. Kilda’s at night to run and dance in the very glade where Harper’s body was discovered.

The girls’ escapades grow weirder as the glade slowly morphs into a Midsummer Night’s Nightmare of a setting. Adding to the suspense is French’s split narrative: Present-time events at St. Kilda’s are juxtaposed in alternating chapters with events from the previous year, when time was running out for the blissfully clueless Lothario Chris Harper.

“The Secret Place” is another eerie triumph for French. By story’s end, she simultaneously makes you wistful for the galloping intensity of lost adolescence and grateful to leave the confines of St. Kilda’s with mind and body intact.

Corrigan is the book critic for the NPR program “Fresh Air” and the author of “So We Read On,” a book about the “The Great Gatsby” and its rocky path to recognition as a classic.

The Secret Place

By Tana French

Viking. 452 pp. $27.95