Assassin's Bullet.

In Assassin's Bullet, Slater plays Robert Diggs, a black ops agent who comes to work for Ambassador Ashdown (Hunger Games star Donald Sutherland), tracking down a vigilante assassin in Eastern Europe. The maverick hit(wo)man has been taking out high-profile targets on the U.S. hit list, and Diggs must uncover the killer's identity before there's an international incident. The usual game of cat and mouse ensues.