The Innocents by David Baldacci

Army special agent John Puller gets a letter from his beloved Aunt Betsy saying something fishy is going on in her small Florida town, the ironically named Paradise. When John goes to Florida to talk to Betsy, he finds her dead, supposedly as a result of an accidental drowning. But he's not so sure. Then he notices someone tailing him. And a couple of Betsy's friends turn up dead. What nefarious goings-on are going on Paradise? John is on his own and not sure who to trust. At the same time, a mysterious giant man  seems to be on his own mission in Paradise and soon the paths of the two men cross. It's all very exciting. And if this story has any basis in fact, very frightening. I liked the character of John Puller and  that of his feisty friend, one star general Julie Carson. So I hope David Baldacci has more books in store featuring these two.