Cabal : an Aurelio Zen mystery
(Book)

An apparent suicide in the Vatican may in fact have been a muder conducted by a centuries-old cabal within The Knights of Columbus. A discovery among the medieval manuscripts of the Vatican Library leads to a second death, Zen travels to Milan, where he faces a final, dramatic showdown. Meanwhile, Zen's lover, the tantalizing Tania, is conducting her own covert operations--which could well jeopardize everything Zen has worked for. -- from Amazon.