The kill list - Frederick Forsyth

The Kill List: a top secret catalogue of names held at the highest level of the US government. On it, those men and women who would threaten the world's security. And at the top of it, The Preacher, a radical Islamic cleric whose sermons inspire his followers to kill high profile Western targets in the name of God. As the bodies begin to pile up in America, Great Britain and across Europe, the message goes out: discover this man's identity, locate him and take him out.

Tasked with what seems like an impossible job is an ex-US marine who has risen through the ranks to become one of America's most effective intelligence chiefs. Now known only as The Tracker, he must gather what scant evidence there is, collate it and unmask The Preacher if he is to prevent the next spate of violent deaths. Aided only by a brilliant teenaged hacker, he must throw out the bait and see whether his deadly target can be drawn from his lair.