Deadly Sin by Raymond Russell 

Set in Rome and London in 1947 and looking back to the First World War, the novel develops the characters of the protagonists from the first novel Deadly Endings in their earlier years.

The Vatican has survived the Second World War, but its cardinals are being mysteriously murdered one by one. Former escaped Nazis and the Mafia jostle for position in a changing world, where Russian Communism is taking over the vacuum left by a deflated and bankrupt Britain and an exhausted Western Europe.

Sam and Phaedra have been called in by a poverty stricken British Secret Service. Can they find the cardinal killer nicknamed the Purple Assassin? Will they get the upper hand on their old adversary Fyodor Poluostrovich from the KGB and will they discover who wants their daughter dead? It’s Deadly and it’s a Sin.