Lindsey Davis 
Death on the Tiber 

Rome is in chaos. The empire of a mobster chief is falling apart following his death. Rivals, fearsome relatives and associates are taking up position to vie for the spoils. With hideous murders in the streets of Rome, a lone female traveller arrives with an agenda of her own. But when her corpse is dragged out of the river bearing signs of foul play, Flavia Albia is drawn in, concerned about her fellow Briton’s fate. Albia’s quest to find the killer becomes deeply personal when she discovers a man at the centre of the plot is an old adversary of hers. Will she be obsessed by revenge? Can she let the past go, or will it consume her?