Killing Cousins

Genealogy, genetics and keen detective work mesh effectively, if ponderously, in this first novel set on isolated Fogge Island off the New England coast. Mort Sinclair is a respected genealogist and lawyer, hired as a consultant by the state police who think his particular expertise in exploring family histories will help them solve three cyanide poisonings in the island's prominent and densely interrelated Gorges family. (Ample genealogical charts are provided to aid the reader in tracing the byzantine family connections.) When more, puzzling murders are committed, Sinclair's astute detective work with library and courthouse documents reveals nasty, long-hidden family secrets: the island's respected doctor is up to his elbows in deceitful practices; the Gorges family fortune was made unscrupulously; and, astonishingly enough, two babies were switched at birth. Sinclair works closely with Sergeant Priscilla Booth, a witty, bright and capable officer who proves to be a relentless though diplomatic interrogator. Their quietly romantic relationship lends strength and continuity to a book overly burdened with complex entanglements and labored explanations. This is the first fiction title for Ancestry Inc. (Mar.)