Frances Crane. The Shocking Pink Hat (1946) 251 pp.
In San Francisco, sleuthing couple Pat and Jean Abbott see a car crash into a hydrant—with a murdered man slumped behind the wheel. The dead man is the estranged husband of a very good friend of the Abbotts, Nancy Leland. Nancy is suspected of the murder, the Abbotts are involved in two more murders, mayhem, and a few other slightly illegal activities. A grim chain of apparently unrelated clues leads them to the murderer, and to a solution of more than passing interest to the Federal Bureau of Narcotics.
Baird & Greenwood 568; Herron; Hubin