The Fifth Gospel by Ian Caldwell

A mysterious exhibit is under construction at the Vatican Museums. The curator is murdered at a clandestine meeting on the outskirts of Rome a week before it opens. That same night, a violent break-in rocks the home of Greek Catholic priest Father Alex Andreou. When the papal police fail to identify a suspect in either crime, Father Alex decides that to find the killer he must reconstruct the secret of what a little-known, true-to-life fifth gospel known as the Diatessaron reveals about the church’s most controversial holy relic. But just as he begins to understand the truth about his friend’s death and its consequences for the future of the Christian church, Father Alex discovers a ruthless stalker is hunting him—an enemy with a vested stake in the exhibit that he must outwit to survive.

Rich, authentic, erudite, and emotionally searing,
 The Fifth Gospel
 is a riveting novel of suspense and a feast of biblical history that satisfies on every level.