Camel Club novels

After witnessing a murder with ties to a prestigious businessman's club, homeless conspiracy theorist Oliver Stone steals a crucial piece of evidence from the scene, and is subsequently pursued by a dangerous member of the club.

Oliver Stone, the leader of the mysterious group that calls itself the Camel Club, is both feared and respected by those who’ve crossed his path. Keeping a vigilant watch over our leaders in Washington, D.C., the Camel Club has won over some allies, but it has also earned formidable enemies–including those in power who will do anything to prevent Stone and his friends from uncovering the hidden, secret work of the government.
Annabelle...

John Carr, aka Oliver Stone-- once the most skilled assassin his country ever had-- stands in Lafayette Park in front of the White House, perhaps for the last time. The president has personally requested that Stone serve his country again on a high-risk, covert mission. Though he's fought for decades to leave his past career behind, Stone has no choice but to say yes.