Relatively subdued doings for abrasive Lt. Leroy Powder of the Missing Persons Bureau at the Indianapolis Police Dept. (Night Cover, Hard Line), who spends less time wisecracking and more time sleuthing this time out--with a couple of serious cases, several minor ones, and a few rough personal entanglements. Powder's primary concern, at least at first, is the disappearance of a shadowy man named Sid Sweet--whose 12-year-old son (recently deserted by Mom too) pluckily soldiers on alone, waiting by the phone for a call from Dad. Could Sweet's absence be related to his mob-connected in-laws, to his strange lack of verifiable life-history? So Powder believes. But his investigation, which eventually leads to the FBI, is interrupted by other cases: the disappearance of a computer-whiz who has propounded a theory, based on statistical data, that someone in Indiana is secretly killing handicapped people by the hundreds; and parental attempts to reclaim a runaway girl who has joined a yuppie cult called ESI (""Enlightened Self-Interest""). Furthermore, Powder's private life is complicated by the appalling behavior of his estranged ex-con son, by his edgy romance with wheelchair-bound colleague Carollee, and by the reappearance in his life of old flame Martha Miles--who just might have ulterior motives. Two of Powder's puzzles will link up in a satisfying, not-too-coincidental way. One of the others will lead to grisly psycho-melodrama, a bit overwrought. And overall, though lacking the black-comic zip of Hard Line, this is a roughly likable, steadily entertaining mixture of gritty procedure, downbeat humor, and middle-age Angst.