``I secretly think of much of my work as family-saving,'' says Kit Deleeuw, the American Way Mall detective (The Last Housewife, 1995, etc.). But it's too late for him to save Linda Lewis and the ex who's stopped phoning the kids or sending support: When Kit goes after Dale Lewis, he finds him dead, followed shortly by Linda herself, killed in an apparent carjacking. The cops accept the coincidence, but Kit--convinced, quite without reason, that the key to Dale's murder lies in the men's support group he attended--sets about infiltrating the group, using as a pretext the true-enough fact that his son Ben's just been suspended for smoking pot in school. Kit, overwhelmed by his infatuation with Linda and his bewilderment over Ben, reacts by dispensing fatherly advice to every other grownup in sight, including the reader (``Hitting is out. Nurturing is in'')--until Katz, suddenly remembering that his hero's supposed to be conducting a murder investigation, rushes to tie Dale's land-development schemes in to a Jersey City mobster, rattle the Fathers' Club cages for skeletons, and produce a sensitive, deeply unsatisfying solution. As casually plotted as the Suburban Detective's first three adventures, but without the edge that made their exotic New Jersey fauna so compelling. This time, Kit's homiletics come across as just plain gassy.