EvenOdds (Wynn Garrett Series #5) by Bruce A. Borders

When a digital interface containing sensitive government documents and classified information is stolen from the Anti-terrorist Operation by the terrorist group ASAD, Wynn Garrett is called into action. His assignment initially is to only retrieve the interface but soon turns into more after ASAD attempts to kill him. Ignoring his original mission of finding the interface, in favor of eliminating the targets, his violent tendencies create a political uproar. His bosses, Thomas Wardahl and Richard Scorby are ordered by the President to immediately shut down operations. Wynn Garrett objects, vowing to complete his assignment. In his usual aggressive approach, Wynn manages to function successfully on his own and the terrorists get more than they bargained for.