The Romanovsky Stain by Duke Zimmer

Jacob Steiner left the intelligence world to join the NYPD where he worked until he was recently terminated for over zealous police work -- he beat the crap out of a child molester and broke the molesters skull in the process. Contemplating a quiet life in Los Angeles, Jacob soon discovers that a lifelong nemesis and former KGB agent, Sergei Romanovsky, has other plans for him.