The Deadly Puzzle. JAKE WAYDE BOOK, #1

Brilliant, renowned chemist Dr. Frederick Rhineman's fascination with genetics is surpassed only by his obsession with intricate puzzles and revenge. His most recent work with pathogens and ethnic heredity has resulted in discovering a formula that can pinpoint people of a specific nationality-and eliminate them. When Rhineman unexpectedly dies of a massive heart attack, his secretary fulfills his last directive.
She mails sixteen letters: four to foreign dignitaries of the world's most volatile countries and twelve to the people Rhineman most hated. Each letter contains clues and a puzzle piece leading to a secret cache of ten million dollars and the lethal chemical formula. One of the letter recipients is an ex-marine turned private detective, Jack Wayde. As the inevitable killing spree ensues, Wayde is unwittingly drawn into the deadly competition.
 He must prevent the formula from falling into the wrong hands while finding out who holds other puzzle pieces, three of whom are women. The circle of suspects is quickly shrinking: Wayde must prevent the formula from getting into the hands of the women and find out who the other puzzle piece holders are before they find-and kill-him.