The Fifth Floor (Michael Kelly Series #2) in Bloomington, MN

Private detective Michael Kelly returns in a lightning-paced, intricately woven mystery. When Kelly is hired by an old girlfriend to tail her abusive husband, he expects trouble of a domestic rather than a historical nature. Life, however, is not so simple.
The trail leads to a dead body in an abandoned house on Chicago's North Side and then to places Kelly would rather not go: specifically, City Hall's fabled fifth floor, where the mayor is feeling the heat. Kelly becomes embroiled in a scam that stretches from current politics back to the night Chicago burned to the ground. Along the way, he finds himself framed for murder, before finally facing a killer bent on rewriting history.