A Kellerman twist that’s all about Isaac

For his new thriller, a unique combination of police procedural and coming of age novel, Jonathan Kellerman has sidelined his longtime series hero Alex Delaware in favor of intuitive but emotional LAPD homicide detective Petra Connor. The volatile Petra made her debut six years ago as protagonist of the novel “Billy Straight,� then reappeared last year in “A Cold Heart,� playing second lead to Alex but nearly nudging the considerably less dynamic doctor from center stage.

“Twisted� would seem to be the author’s way of officially designating her as a new series lead. But there’s an “All About Eve� element present in the form of Isaac Gomez, a brilliant but geeky prodigy of 22 who possesses awkward charm to spare and deductive prowess to rival the great Sherlock Holmes.

Isaac’s scholastic genius and Latino heritage have earned him a politically endorsed internship at the Los Angeles Police Department’s Hollywood Division while he works on a doctoral dissertation, “Discriminating and Predictive Patterns of Solved and Unsolved Homicides in Los Angeles Between 1991 and 2001.� Naturally Petra’s chauvinistic captain assigns her the unpopular task of acting as mother hen to Isaac. Naturally the boy wonder’s research yields a heretofore undetected homicidal pattern destined to place them both in peril: For the past six years, a fatal cranial bludgeoning has taken place at midnight on June 28, a date that is rapidly approaching.

This should be enough to hook any mystery fan. Add to it Kellerman’s talent for creating believable characters, be they workaday people or West Coast oddballs, and matching them in interpersonal relationships that seem totally natural, no matter how bizarre. Here, the detective’s minimal tolerance for Isaac smoothly segues into genuine affection, while his schoolboy crush on her begins to fade as he comes of age, toughened by L.A.’s mean streets and emboldened by the glare of celebrity.

Isaac’s revelation prompts Petra to reopen a half-dozen cold cases, with attendant family members, friends, suspects and grumpy original investigators to be visited and evaluated. She’s also working on a drive-by shooting at a hip-hop club, a convoluted quest for justice involving gangstas, health clinics and a family of con artists.

Additionally, she must deal with the aforementioned captain, who’s looking for any excuse to dump her, and fret about her former partner and current lover, Eric Stahl, whose new Homeland Security squad gig keeps him incommunicado as he faces death in international trouble spots.

Isaac has his own subplots. His boyhood friendship with a neighborhood dope dealer has piqued the interest of Internal Affairs. A roaming crew of street thugs is out for his blood. And a research librarian with whom he has had a surprising -- some might say shocking -- sexual dalliance now seems to be stalking him.

Though numerous plot tendrils make for a beguiling read, they also place an added burden on the author. Kellerman gathers the loose ends, but he does so a bit too quickly and too tidily in some instances. For example, Isaac comes by a final, crucial bit of evidence without much effort or brainwork. And the solution to Petra’s difficulty with her boss, though subtly foreshadowed, smacks of deus ex machina.

Still, the novel delivers full measures of suspense, humor and sleuthing. And it introduces the amazing Isaac, who one assumes will be discovering ever more homicidal patterns with the dishy Petra or on his own. Kellerman has published four novels in the last two years and co-authored “Double Homicide� with his wife, crime novelist Faye Kellerman. For a writer that prolific, it makes sense to have several series characters waiting in the wings.

Dick Lochte is a critic of crime fiction as well as co-author, with attorney Christopher Darden, of the legal thriller “Lawless.�

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Twisted

A Novel

Jonathan Kellerman

Ballantine Books: 372 pp., $26.95