Mo Hayder's 'Poppet' takes nuanced, compelling look at evil Since introducing Detective Inspector Jack Caffery 14 years ago in "Birdman," Mo Hayder has written some of the grisliest crime fiction in recent memory. Caffery's cases in London and, later, in Bristol's Major Crime Investigation Team, have included the murder and bizarre postmortem autopsies of women by a surgically trained serial killer, abducted children and sadistic African rituals. That's enough evil to keep readers awake long after the cases are solved. But not all evil is so easily dispatched, in life or in DI Caffery and his colleague Sgt. Flea Marley's universe. As Hayder's skills have evolved, so has the manner in which she depicts evil - less sensationally and, ironically, more frighteningly, recalling in the process a line from a W.H. Auden poem: "Evil is unspectacular and always human/ And shares our bed and eats at our own table." Nowhere is Hayder's portrayal more nuanced and compelling than in "Poppet," the sixth entry in the series. Parallel plotlines form the backbone of the novel. One involves the strange occurrences at the Beechway High Security Unit, a psychiatric hospital that had been a 19th century workhouse and a poorhouse for the homeless before its present incarnation. Patients and an increasing number of staff are fearful that the Maude - believed to be the ghost of the sadistic matron from Beechway's workhouse days - has been wreaking havoc on one of the wards, carving biblical quotations into patients' flesh, causing them to gouge out their eyes, mutilate themselves and worse. The suspicious death of a female patient has even gotten to AJ LeGrande, a conscientious senior nursing coordinator whose dreams are infected by images of the Maude and who feels when he visits the dead woman's floor "an unease he gets from years of experience. Like a vibration in the walls. The second plotline is the ongoing investigation into the disappearance of Misty Kitson, a 25-year-old model and footballer's wife who vanished after leaving a rehab facility some 18 months before. Misty's mother, Jacqui, has come to Bristol to demand more attention be paid to her daughter's case. Caffery is as distressed about Misty's disappearance as her mother but for vastly different reasons: He has a suspicion about who the killer might be but has refrained from pressing the case while he tries to find a way to protect those who are implicated. "He's had several months to think about this problem and he's got a long-game walking around in his head...," writes Hayder. But for the solution to work he needs the cooperation of one person.... And he still doesn't know how to make that approach. It could go so badly wrong. Meanwhile, Caffery is contacted by AJ, whose nagging doubts about the incidents at Beechway have prompted him to contact the police, contrary to the wishes of Melanie Arrow, the facility's administrator (and AJ's new lover). AJ realizes that power outages have occurred just before each of the attacks and believes one of the patients, the deeply disturbed Isaac Handel, may be behind them. To get to the truth, Caffery and AJ must explore the teenage Handel's horrific murder of his parents some 15 years before as well as the circumstances surrounding his sudden discharge at the recommendation of Arrow, who seems to have downplayed the danger Handel presents to the community to get him out of her facility. Tautly told in the present tense in chapters that alternate primarily among Caffery, AJ and Flea Marley's points of view, "Poppet's" plot is as complicated as its villains and heroes. Characters central and peripheral to the action are full of contradictions, including Misty Kitson's grief-numbed yet raging drunk of a mother and Marley, who's grieving the loss of her parents in a diving accident some years before while wrestling with her feelings for Caffery. "There must, somewhere, be an equation for how long grief lasts," she thinks. If you can map the human genome and work out what Martian soil is composed of, why can't you calculate when the hurt will be over? Hayder's rich psychological portraits of her characters and their sorrow over past loves and past deeds outshine the gore of the early scenes and makes "Poppet" a compelling mystery that will cause fans and new readers alike to ponder not just who did it, but why. Woods is the author and editor of eight books, including four novels in the Charlotte Justice mystery series, and is a member of the National Book Critics Circle. Poppet A novel Mo Hayder Atlantic Monthly Press: 380 pp., $25