"Tender Prey" is a thriller, but mostly it is the characters rather than the intrigue that will interest the reader.

The murderer, Belfast-born Robert Wallace, is revealed at the beginning. His identity is discovered by New York cop Jim Hackett long before the novel's denouement. So what we have, interspersed with the story of Hackett's attempt to find Junie Stephens, the missing little girl, and her kidnaper-killer, is a chronicle of the lives of Wallace, alias John James, and Hackett: an explanation of why the Orangeman became a child-killer and the Irish-Catholic Brooklyn lad became a cop.

Sharing top billing with these two is Junie's older sister, Ali, old beyond her 13 years, more capable of dealing with the cruelties of the Great Depression than her sad, gullible mother.

Motherhood does not fare well under Patricia Roberts' pen. Wallace was abandoned by his mother and brought up in an unfriendly orphanage. When he was old enough to be of some use, his mother reclaimed him so he could work in her Belfast pastry shop. After living with her four years, he packed his satchel and left.

"She is dead now Wallace says . Not too long ago I ran into someone who had known the shop. He told me that she had become R.C., like the neighborhood, before she died. There's no accounting for the actions of a woman without character, and to this day I don't know if she turned so that she would fit in better--she was a great believer in accommodation, when it suited her--or if she indeed got the Papist call. Perhaps she did. She had the kind of ruthlessness that converts with age to sentimentality."

Later, Wallace is abandoned by his wife. He barely misses her, but he does miss his stepson Robbie. He preys on lonely widows, marries them if he must to relieve them of their meager savings (the only mistake he made, he says, is the time he took up with a rich widow, who consequently was suspicious enough to bring in the law before he could escape with the cash).

Hackett's mother is a lush. "You look at her blouse, you know every meal she's had the last week," he tells his high school buddy Bobby Brennan. Hackett has remained single while carrying on an affair with the wife of an acquaintance, a woman who is probably barren.

Roberts' story takes place in the mid-1930s. Wallace/James courts Mary Stephens through an ad in Police Gazette. He moves in with Mary and her two daughters, leaving each day, he says, to prepare the opening of his home and his shop on the beach. He senses and returns the hostility of the older child, Ali, while favoring the 10-year-old Junie. A month after marrying Mary Stephens, Wallace/James takes Junie on a trip to the beach. They don't return.

From here, Hackett, who works for the missing persons division of the New York Police Department, develops a special relationship with Ali, who drops enough clues so that Hackett eventually identifies his man.

The novel has moved slowly up to this point, content to let Hackett, and the reader, ponder the character of Junie's abductor. Suddenly, Hackett and his skeptical boss, Detective Long, plunge headlong into a horrifying, grisly meeting with Wallace.

Roberts, who was born in England of Scotch-Irish parents but now lives in New York, brings the crazed Orangeman to life--his chapters are written in the first person--and her New York of the Depression years is as believable as William Kennedy's Albany of the same period. And she is as successful as Patrick McGinley in "Bogmail" in maintaining suspense and interest in a story in which we know the identity of the murderer from the very beginning.

Although the psychological structure of Wallace is at the heart of this novel, it is not entirely clear how or why he converted from a woman-hater to a child molester. And I found the inclusion of the sex life of Hackett superfluous. But Roberts aimed high with her first novel and came closer to her target than most first-timers with less ambition.

"Tender Prey" is one of five novels that Doubleday has rewarded with a special advertising and promotional campaign. Three of the five are first novels and none is by a well-known author. At a time when the giants of the typewriter have been receiving almost all of the publishers' largess, it is encouraging that Doubleday is giving full support to such a promising writer as Roberts.