The Delphi Technique — J.C. Ryan

A delusional genius bent on restoring an empire must be stopped. Rex, Catia, and Digger are on Rhodes Island, Greece, when an assassin kills two people right in front of their eyes. They jump into action to help. The assassin flees, but Rex and Digger give chase, and when they catch up with her, she commits suicide. Back at their hotel, while busy reporting the incident to John Brandt, three masked men storm into their room with guns blazing. Thus, the trio is drawn into a CIA operation to uncover the identity and whereabouts of a terrorist mastermind about to unleash death and destruction across Europe.