Robert Ludlum's the Geneva Strategy

"On one evening in Washington, DC, several high-ranking members of government disappear in a mass kidnapping. Among the kidnapped is Nick Rendel, a computer software coding expert in charge of drone programming and strategy. If his dangerous knowledge is revealed, his kidnappers could reprogram the drones to strike targets within the United States. Jon Smith and the Covert-One team begin a worldwide search to recover the officials, but as the first kidnapping victims are rescued, they show disturbing signs of brainwashing or mind-altering drugs"--