The Fourth Crow

Scotland Yard detective Harry Fathers reprises his remarkable sleuthing in this trenchant, multilayered mystery. Britain's MI5 intelligence agency, bedeviled by apparent security leaks, selects the tenacious Fathers to find the traitorous ``crow.'' Fathers agrees to the job, interrogates possible perpetrators and turns up intriguing, if not damning evidence. At the same time, his wife, Sarah, resentful of his relentless work schedule, is spending a suspicious amount of time out of the house. He must attempt to placate her while he works on yet another investigation, this one of a savage outbreak of killings within East End gangs. An engaging resolution to the street wars provides a respite as Fathers determinedly continues ``crow-hunting.'' There is a startling and unusual denouement, though Sarah remains unappeased; presumably her questions will be addressed in Fathers's next outing. Smith ( Fathers' Law ) presents players and develops plot with an expert hand; however, his dialogue, while often wonderful, has patches of impenetrable idiom. (Dec.)