Ruso and the root of all evils - Ruth Downie

Gaius Petreius Ruso, doctor to the Legions, is about to return home to Gaul after many years' absence. Little does he realize the letter summoning him back has been forged, or that the sunny Mediterranean lifestyle conceals a dark threat lurking at every corner. His family are in horrific debt to dangerous men and when the principal creditor, Severus, is poisoned in the Ruso home they become the primary suspects in his murder.

But the crimes go far deeper. What role did Severus play in the deliberate sinking of a cargo ship? Who are the brutal investigators sent by Rome? And how worrying is the outbreak of the new religion, Christianity, in the neighbourhood? When Ruso takes a job stitching up gladiators in the local amphitheatre, matters come to a head. He's literally in the lion's den and even Tilla, his loyal servant, may not be able to save him from the clutches of a most devious murderer . . .

Ruso and the Root of All Evils, is published in the US as Persona Non Grata.