Book 8 in The Phoenix Chronicles.
"As Brady Hawk and the Magnum Group travels to extract a Russian general who's defecting, they learn of a plot by members of the FSB to assassinate a high-level U.S. official. When they return home, they find that all their assumptions about who's behind the plot and why are wrong, sending the team chasing an assassin who is already two steps ahead. And with the Russian assassin on the loose, no one is safe. No one."