Nemesis by Lindsey Davis

The excerpts follow the Roman investigator Marcus Didius Falco as he deals with profound grief over the death of his baby son, even as he is forced to manage the unexpected inheritance following the death of his estranged but wealthy father. Falco's duties quickly expand when he and his friend, the vigil Petronius Longus, begin investigating a series of brutal, ritualistic murders centered on a feral family of freedmen known as the Claudii who inhabit the Pontine Marshes. The investigation is continually disrupted by Falco’s nemesis, the high-ranking spy Tiberius Claudius Anacrites, who seems suspiciously committed to shielding the criminal family from the law. Falco discovers that his legal status and fortune may be jeopardized by his father's pregnant lover, the contortionist Thalia, should she give birth to a son. The plot culminates in the realization that Anacrites has expertly manipulated Falco into eliminating the murderous Claudii to prevent them from exposing his own humble family background. Ultimately, Falco must confront the primary killer, Nobilis, while navigating the immense fortune and new responsibilities left behind by his father.