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My Ex-Best Friend is indisputably a mystery, opening with an unexpected death and a whodunit question. That said, the book is subtitled A Novel of Suburbia—and that’s how author Beth Brophy prefers to think of it.

“I’ve always modeled myself after Susan Isaacs,” says the Chevy Chase, Md., resident, referring to the quintessential chronicler of suburban womanhood—whose books often get shelved alongside mysteries, as well. “I don’t take offense if someone calls it a mystery,” Brophy says. But it’s not a genre she’s drawn to: “I really hadn’t read a lot of mysteries” before tackling the book.

Writing My Ex-Best Friend, her first novel, took Brophy several years, during which time she, like protagonist Claire Newman, juggled writing and child-rearing careers. The novel is set in Bethesda, pretty much Brophy’s own home territory, but the author says she had no real-life precedent for its core relationship: the mostly broken bond between Claire and a childhood friend. When this long-estranged pal, Lydia, dies suddenly after a cryptic call to Claire, Brophy’s heroine uses her skills as a “relentless snoop” to figure out what led to two deaths: that of Lydia and that of the friendship.

To write My Ex-Best Friend,

Brophy, a former reporter for Forbes, USA Today, and U.S. News and World Report, had to research pharmacology, photography, and finance. (Her banker husband, Arthur Karlin, was a ready source for the money info.) “The most difficult part of making the switch [to fiction],” she has said, “is that in journalism, the goal is to convey as much information as soon as possible. In fiction, particularly mysteries, the goal is to withhold information and release little clues along the way, but not too quickly.”

Brophy says that her book’s title tends to grab women’s attention. “You don’t see that many novels that deal with women’s friendships,” she notes—or at least not many that explore the kind of intense connection felt between her two characters and the pain of its inexplicable rupture.

She plans to keep working the suburban beat with another Claire Newman book, this one set three years after the first. One reason for the time lapse is personal: “I wanted her kids to be older,” says Brophy, whose own kids are in their teens. But there’s also the plausibility issue, bane of mystery writers and journalists alike. After all, “how many murders will [Claire] run across?”—Pamela Murray Winters