Dancer's Debt

Helen Crane, a beauty ''men build dreams around,'' hires private eye Alo Nudger to find out what's troubling her lover Jake Dancer. Middle-aging, old-shoe Nudger tails Dancer and manages to save him from a couple of strong-arm men. Dancer handsome, feckless, an alcoholic and compulsive gambler is vague about the money he owes, and Nudger learns that Helen, working for an ''escort service,'' plans to move ''up'' to prostitution to help pay Dancer's debts. Then Dancer vanishes, Nudger's lover Claudia is abducted, and the story ends with the uncovering of a grisly, sadistic snuff-film operation. Readers may object to the slow pace, to Dancer's tiresome little-boy-lost routine and to a pat, if tangled, resolution. Nudger's preoccupation with buying a used car is stressed as much as his concern for Claudia, and, except for the Mississippi River as a dumping place for corpses, we don't get much St. Louis color.