Seville Communion: The Infamous Life of Emma Hamilton by Arturo Perez-Reverte

Murderous goings-on in a tiny church draw the Vatican into the dark heart of Seville. A hacker gets into the Pope's personal computer to leave a warning about mysterious deaths in a small church in Seville that is threatened with demolition. Father Quart, a suave Vatican troubleshooter is sent to investigate.

Experience has taught him to deal with enemies of the Church in all their guises, but nothing has prepared him for the stubborn faith of Father Ferro, or the appeal of the lovely Macarena Bruner, desperate to save the church and her ancestors from her ex-husband, the ruthless banker Pencho Gavira. As Quart is drawn into an intrigue as labyrinthine as the streets of Seville, soon more than his vocation is in danger.