A Refiner's Fire - Donna Leon

In the thirty-third installment of Donna Leon's magnificent series, Commissario Guido Brunetti confronts a present-day Venetian menace and the ghosts of a heroism that never was
Around one AM on an early spring morning, two teenage gangs are arrested after clashing violently in one of Venice's squares. Commissario Claudia Griffoni, on duty that night, perhaps ill-advisedly walks the last of the boys home because his father, Dario Monforte, failed to pick him up at the Questura. Coincidentally, Guido Brunetti is asked by a wealthy friend of Vice-Questore Patta to vet Monforte for a job, triggering Brunetti's memory that twenty years earlier Monforte had been publicly celebrated as the hero of a devastating bombing of the Italian military compound in Iraq. Yet Monforte had never been awarded a medal either by the Carabinieri, his service branch, or by the Italian government.
That seeming contradiction, and the brutal attack on one of Brunetti's colleagues, Enzo Bocchese, by a possible gang member, concentrate Brunetti's attentions. Surprisingly empowered by Patta, supported by Signorina Elettra's extraordinary research abilities and by his wife, Paola's, empathy, Brunetti, with Griffoni, gradually discovers the sordid hypisy surrounding Monforte's past, culminating in a fiery meeting of two gangs and a final opportunity for redemption.
A Refiner's Fire is Donna Leon at her very best: an elegant, sophisticated storyteller whose indelible characters become richer with each book, and who constantly explores the ambiguity between moral and legal justice.