We Call Upon The Author Am Searching For A Book.Can't Remember Author,name,etc.Set In Ireland,re. A Fake Priest Plot To Kill The Pope.

Am searching for a book.Can't remember author,name,etc.Set in Ireland,re. a fake priest plot to kill the pope. - we call upon the author

In Scripture, I believe, in the 70's / 80 can mean a Soviet planted "spies" or rather, a spy buried upon.Also act on complaints, a tunnel under the church where the pope visit.Meant interrupt the peace talks / Cold War hardware and Ireland.