Assassin's Bullet (2012)

Field Agent Robert Diggs walked away from his career in the FBI and accepted the position of Cultural Attaché in Sofia, Bulgaria for one reason: to escape the memories of his wife's death for which he blames himself. However, when an unknown vigilante begins killing high-priority terrorists from America's Most Wanted list, the FBI and CIA request he take on the case, and with the U.S. Ambassador's persuasion,