From amazon.com:

Detective Alex Cross and Bree's wedding plans are put on hold when Alex is called to the scene of the perfectly executed assassination of two of Washington DC's most corrupt: a dirty Congressman and a scheming lobbyist. Next, the elusive marksman begins picking off other crooked politicians, sparking a blaze of theories--is the marksman a hero or a vigilante? The case explodes and FBI agent Max Siegel battles Alex for jurisdiction. As Alex struggles with the sniper, Siegel, and the wedding, he receives a call from his deadliest adversary, Kyle Craig. The Mastermind is in DC and will not relent until he has eliminated Cross--and his family--for good.