Siren in the Night(1943)
(The tenth book in the Colonel Primrose Mystery series)
A novel by Leslie Ford
The eerie wail of a siren in the night spelled MURDER. The most important man in San Francisco lay, violently murdered, in his huge house on a cliff above the city. Swiftly the mystery deepened, involving a strange light that burned night and day, the lovely stepdaughter of the victim--and a man she should never have known. And soon that irrepressible lady detective, Grace Latham, was caught up in her most tantalizing case.
Used availability for Leslie Ford's Siren in the Night