It's Christmas Crime (7) - Magdalen Nabb

The late Magdalen Nabb wrote fourteen Marshal Guarnaccia books which were published over eighteen years, the last being published posthumously in 2008. The first in the series, which introduced the Florentine detective, was Death of an Englishman:

Publisher's blurb:
Introducing Marshal Salvatore Guarnaccia of the Florentine carabinieri, a Sicilian stationed far from home. He wants to go south for Christmas to spend the holiday with his family, but he is laid up with the 'flu. At this awkward moment, the death of a retired Englishman is reported. Who has shot Mr Langley-Smythe in the back? And why has Scotland Yard felt it appropriate to send two detectives, one of whom speaks no Italian, to 'help' the marshal and his colleagues with their enquiries? Most importantly for the marshal, ever the Italian, will he be able to solve the crime sufficiently quickly for him to be able to join his family over the holiday season?