The Book of Turns. Book 7 of the Peacetaker Series

A parish priest is found murdered in a small community church in Wyoming, a victim of a cleverly-staged home invasion. The event, while disturbing, is not sensationalistic enough to last in local newspapers longer than a day. A few hours later, further upstate on a shabby dude ranch that's in financial trouble, a guest is found dead in his cabin. The ranch owners take everything the guest had that could be of value, before calling the sheriff.
When the death is ruled to be natural causes, and no one steps forward to claim the body, the case all but fades into obscurity. Two years later, the FBI is frantically searching for Carter and Stella, because the bizarre and tabloid-worthy events that had been happening these past two years, have reached a boiling point. Rivers changing course and campsites relocated clear across the lake could be explained through climate shift and vandalism.
A war veteran who lost his leg in the service of his country and then woke up one morning with both legs healthy and functioning as these have not in a long time, can be attributed to questionable experimental procedures.  A woman inheriting a fortune from a phantom relative could be just a great scam-or a hoax. But when several distinguished experts examine a medieval manuscript that has been re-written in modern-techno language, as authentic, the world and its media begin to take notice.
And when someone in the National Archives wonders abstractedly what would happen if one day Washington woke up to find the Declaration of Independence re-written in a similar manner, things start hopping and all the security agencies in the country go on high-alert. It's this last event that brings the FBI Special Agent Saunders to England, to come sit down in a roadside diner across the table from his friend Carter, and insist that he and Stella cut their vacation short because the world is on the brink of global catastrophe.
What is happening is simply.not of this world.