Robert Ludlum's The Bourne dominion / Eric Van Lustbader.

Bourne's enemies are gathering force. Severus Domna, a secret and ancient cabal, has called forth its members from around the globe, with one objective: to vanquish the last person capable of destroying their bid to de-stabilize the world economy - Jason Bourne. But how can they possibly succeed where so many others have failed? By turning Bourne's most trusted friend into his greatest - and most deadly - enemy. Boris Karpov has reached the pinnacle of his career. He has taken over one of the most powerful security organisations in the world - but at a price. Karpov agreed to a devil's pact with the former head, and now he has to deliver. But it's far worse than anything Karpov could have imagined - he must kill his oldest friend, Jason Bourne. Now Bourne finds himself in a world where friend and foe go hand-in-hand. Bourne's journey will lead him down a path of brutal murder and destruction - one from which there is no escape...