Victory Garter. Maggie Sullivan mysteries, #9

The brutal hit-skip death of a young woman is being written off as an accident until 1940s private investigator Maggie Sullivan finds signs pointing to murder. Charlotte Littlefield, a girl with "a past" was about to marry into one of Dayton, Ohio's, most prominent families and was staying with them to get better acquainted and smooth her rough edges. Did someone in the household object to her upcoming union? A frightened, incoherent phone call made moments before she fled the mansion and met her death suggests another possibility: Charlotte had seen - or heard - something she shouldn't have. Maggie spends frustrating hours in a mansion full of suspects.
One wing houses a laboratory where the head of the family and his staff work on something hush-hush which the War Department needs as the war in Europe nears its end. Upstairs, his once-vibrant wife sits in her room a near invalid in the aftermath of polio. Their three grown children are a tangle of resentments, jealousy and anger. A second murder raises the specter of someone targeting the family, or one of its members.
Undeterred by a black eye, Maggie tracks down clues in high-class brothels, burlesque theaters, bars and ivy trellises. Before she can use her last bit of proof, she is plunged into a harrowing cat-and-mouse chase with the killer in surroundings where a single misstep could cost dozens of lives.