Dead Lagoon

Blurb

Dead Lagoon is a novel by Michael Dibdin, and is the fourth entry in the popular Aurelio Zen series.
Moonlighting, Zen engineers a posting to his home town of Venice on a pretext in order to investigate the disappearance of an American millionaire on behalf of his American ex-girlfriend. He needs the extra money to set up home with his new girlfriend with room for his aged mother.
His investigations lead him into conflict with a charismatic local rising politician and a childhood friend before he discovers a shocking truth about his supposed dead father. Although he actually does get to the bottom of both his overt and covert enquiries, he leaves Venice in frustration and with childhood illusions shattered.