Through the first half of this 1930s kidnap/murder investigation-novel, there's promise of a masterful blend of psychology and suspense in the understated manner of Ruth Rendell or P. D. James; and, even though Roberts' debut thins out routinely in its later sections, she emerges as a firm, quiet stylist with a bright future. ""I bother only with widows."" So begins the opening chapter here--as Robert Wallace, the novel's psycho-villain and sometime narrator, starts filling in his grim life-story: abandoned by his widowed Belfast mother, separated from his brother and sister, later betrayed by his wife, Wallace has become a New York con-man with a loathing for widows and a perverse attraction to little girls. And Wallace's latest victim is vulnerable, gullible Mary James, whom he has married, lied to. . . and now robbed of her younger daughter, lovely ten-year-old Junie. Where has ""John James"" (Wallace's alias) disappeared to with little Junie? That's the question for Detective Jim Hackett, a moody sort with a half-commitment to his childless, adulterous mistress. Hackett has few clues--most of them teased out of the memory of Junie's smart, spunky older sister Ali--until Mary receives a grisly package: a carved doll in an Altman & Co. box, dressed in Junie's clothes and topped with Junie's real hair. And then, while Wallace's crazed narration confirms the fact of Junie's murder (and dismemberment), Hackett follows the Altman's clue to Wallace's identity, deduces his whereabouts from Ali's recollections, and heads for the killer's hideout. . . where a violent showdown ensues; but it's too late to prevent Wallace's second murder. Unfortunately, Roberts never succeeds in making Hackett's inner turmoil fully convincing--so his traumatic final chapters (an outburst of savagery, a hard-won commitment to love) don't quite satisfy. The final section of suspense, too, is shakily handled: the irony and tension of a similar twist in James' Innocent Blood are missing here. Still, the deduction is sound, the tone is chillingly restrained, Ali is an engaging presence--and readers partial to anatomy-of-a-crime fiction will find this a flawed but strong example of the genre, with effectively underplayed period-N.Y. atmosphere.