The Fifth Assassin (The Culper Ring Series)

From John Wilkes Booth to Lee Harvey Oswald, there have been more than two dozen assassination attempts on the President of the United States.
Four have been successful.
But now, Beecher White--the hero of the #1 New York Times bestseller The Inner Circle--discovers a killer in Washington, D.C., who's meticulously re-creating the crimes of these four men. Historians have branded them as four lone wolves. But what if they were wrong?
Beecher is about to discover the truth: that during the course of a hundred years, all four assassins were secretly working together. What was their purpose? For whom do they really work? And why are they planning to kill the current President?
Beecher's about to find out. And most terrifyingly, he's about to come face-to-face with the fifth assassin.