Friends in High Places by Donna Leon

Venetian cop, Commissario Guido Brunetti, wonders whom he knows to bring pressure on a local government department, to investigate the lack of official building approval on his apartment. But when that same official phones him at work, clearly scared by some information he plans to give Brunetti, and is later found dead after a fall from scaffolding, something is clearly wrong, something with far greater implications than the fate of Guido's own apartment. Brunetti's investigations take him into the unfamiliar areas of Venetian life - drug abuse and loan sharking - while the deaths of two young drug addicts, and the arrest and release of a suspected drug dealer, reveal, once again, what a difference it makes in Venice to have 'Friends in High Places'.