Death in Blue Folders — Margaret Maron

Blackmail had been a profitable sideline for attorney Clayton Gladwell until someone put an end to it -- and to him -- with a well-placed bullet. -- Lieutenant Sigrid Harald of the New York Police Department soon finds that opening the dead man's "personal" case files is like lifting the lid of a star-studded Pandora's box. Whose ancient secret has furnished a motive for murder? And why now?

The millionaire's kidnapped grandson has finally been found; Hollywood's golden girl killed herself years ago; the most acid-tongued member of the fabled Algonquin Round Table is an aging recluse; and the senile heir to an Austrian fortune is tucked away in a nursing home.

For endless sticky midsummer hours, the police race down blind alleys - then a second and a third victim fall to the faceless killer, and Sigrid must use all her wits to decipher the mystery of Clayton Gladwell's blue folders before death strikes again...