Rosemary Rowe 
Requiem for a Slave [EPUB ebook] 

Ancient Roman freedman and pavement maker Libertus investigates the death of the pie-maker and the disappearance of his slave amid 'green man’ sightings
Libertus has an important order to fulfil for Quintus Severus who has commissioned a magnificent new mosaic. But when Lucius, the pie-maker, is found dead in Libertus’ workshop, and Libertus’ faithful slave Minimus is missing, he is once again dragged into a criminal underworld.
Even more mysterious is the sighting of a ‘green man’ lurking outside his workshop around the time the murder took place.
Can Libertus find Minimus, clear him of the murder of Lucius, and discover who really killed the pie-seller, and why? The omens aren’t looking good…