Frederick Forsyth's Icon

A former US Operative, who lived in Russia in his earlier years and had been married there with a child, comes out of retirement to face down a former enemy, now running as a candidate for President in modern Russia. Working with a Russian policewoman, they work to uncover a plot to use biological weapons against certain factions of the Russian people to commit genocide. The virus would also be released in other populations, but would be treated making the candidate a hero. A side plot has the agent being reunited with his long lost daughter.