This is book number 4 in the Commissario Guido Brunetti Mysteries (Audio) series.
A truck crashes and spills its dangerous cargo on a treacherous road in the Italian Dolomite mountains. Meanwhile, in Santa Lucia, a prominent international lawyer is found dead aboard an intercity train.
Suspecting a connection between the two tragedies, Brunetti digs deep for an answer, stumbling upon a seedy Venetian bar that holds the key to a crime network that reaches far beyond the laguna. But it will take another violent death in Venice before Brunetti and his colleagues begin to understand what is really going on.