City of Vengeance - D V Bishop
We are all huge historical crime fiction fans and this one is a must if you like CJ Sansom and Laura Shepherd-Robinson.
The setting is Florence, 1536. A prominent Jewish moneylender is murdered in his home, a death with wide implications in a city powered by immense wealt. Cesare Aldo, a former soldier and now an officer of the Renaissance city's most feared criminal court, is given four days to solve the murder. During his investigations Aldo uncovers a plot to overthrow the volatile ruler of Florence, Alessandro de' Medici. If the Duke falls, it will endanger the whole city.
But a rival officer of the court is determined to expose details about Aldo's private life that could lead to his ruin. Can Aldo stop the conspiracy before anyone else dies, or will his own secrets destroy him first?