Walk the Dark Streets — William Krasner

After years of frustration, both Janice Morel's beauty and her hope for a stage career were fading fast. She was sure she'd gotten her big break when an agent promised her a job onstage -- even though she had to turn to blackmail to come up with the money he wanted in return. When Morel is found stabbed to death in a shabby hotel room, few people who knew her can say they're sorry.

There is no lack of suspects among the con men, gangsters, and petty crooks who frequent the Club Trinidad where Morel worked, as Captain Sam Birge of the Homicide Squad begins his investigation. But it's up to Birge, with the help of his ambitious lieutenant and the diary Morel left behind, to find out just which one wanted to see her dead badly enough to do the killing himself.

First published in 1949, Walk the Dark Streets is a classic noir mystery by one of the masters of the genre.