Death in the Devil's Acre — Anne Perry

When a doctor is found brutally murdered in the lurid section of London aptly named "Devil's Acre;" even its most hardened residents are stunned. But shock soon turns to horror when Inspector Pitt discovers three more bodies with the same gruesome "calling card": a stab wound in the back and a rather inexpertly executed mutilation....

As Pitt and his wife Charlotte race against time to find the killer, a treacherous mystery unfolds. And no one, not the lowest brand of ruffian or the most established aristocrat, will come out unscathed....