The Silver Pigs by Lindsey Davis
For confiential informer (an Ancient Roman private eye) Marcus Didius Falco, it seems like a pretty straightforward case. Young, beautiful, and aristocratic Sosia Camillina is being followed by some unsavory types because of something her Senator uncle has hidden in her bank box. That something turns out to be a 200-pound lead ingot filled with silver – a silver pig. Sosia’s uncle claims that the pig is proof of a plot, one that could bring down the Empire. Falco thinks it’s part of a plot too, a plot that has already gotten one person killed and if he’s not careful he’s going to be next.