Dekok and the Sorrowing Tomcat

``Cunning Pete'' Geffel is the type of lowlife crook Detective-Inspector DeKok likes. An ``innocent blackmailer,'' Geffel plays by a set of ambiguous moral rules that are always shifting but that cry out for vengeance when violated. Now, someone has violated them--with a dagger right between Geffel's shoulder blades, and DeKok is about to jump into the fray when ordered by his superior to investigate a $3 million robbery. Soon the two investigations intertwine and the plot's twists and turns include the discovery of a suspect's body in a car, atop a pile of $750,000 in bills. DeKok is up to his old tricks: staging an arrest, breaking and entering, drinking Cognac at Little Lowee's criminal hangout. DeKok also receives help from a source he'd rather not have: Geffel's revenge-seeking girlfriend. In the end, however, the inspector's solution relies on his knowledge of those ambiguous moral rules by which Amsterdam's petty crooks and red-light-district denizens abide. This formulaic entry is far from Baantjer's ( DeKok and the Dead Harlequin ) best, but the pages turn easily and DeKok's offbeat personality keeps readers interested. 35,000 first printing; author tour. (Mar.)