And Then You Die - Dibdin, Michael

Aurelio Zen was dead to the world. Under the next umbrella, a few desirable metres closer to the sea, Massimo Rutelli was just dead. Inspector Zen is back, but nobody's supposed to know it. After months in hospital recovering from a bomb attack on his car, he is lying low under a false name, waiting to testify in an imminent anti-Mafia trial.