Freefall / Adam Hamdy.

"Eight months after confronting Pendulum, John Wallace is losing himself in a dangerous warzone in a misguided attempt at penance for what he has done. But an assassination attempt makes Wallace realise that he has once again been targeted for death. This time, Wallace is prepared and, tracking down his would-be assassin, he discovers a link to his nemesis, Pendulum. The link is the missing piece of a puzzle that has tormented FBI Agent Christine Ash ever since they confronted Pendulum, but with no Bureau support she has been unable to pursue her case. Wallace's proof breaks it, but also exposes them both to terrible danger. Confronted by a powerful, hidden enemy, Ash and Wallace must overcome impossible odds if they are to avert a dangerous challenge to the networked world that threatens to destroy our way of life"--

"John Wallace survived the Pendulum threat, if barely--now he has to find out who he can trust in this high-octane follow-up to his action-packed novel debut"--