Dominic's congressman-sleuth Ben Safford here has to investigate the murder of Shirley Knapp, a lobbyist for private power companies, in the wake of a scandal when it is revealed that she has bribed a fellow politician to alter his vote in a crucial area. The obvious suspects are limited to three, but those familiar with these writers' work won't necessarily assume that they are the only possibilities. The denouement is slightly contrived, but Safford's political insight is logically worked out to reveal the culprit. ( )