Hell Cat by Arnold Marmor (Merit Books, 1961)
As noted before, Arnold Marmor — not a pen name — was a regular guy in the detective, crime, and SF pulps in the 40s and 50s, then turned to, as many hacks did, the sleaze houses that marketed fine genre literature as smut.
Hell Cat opens in a strip club with a new dancer on stage — she calls herself El Gato, wears a cat suit she strips off, keeps a cat mask on the whole time. The men go wild for her. But it seems she may be a jewel thief.
The book is narrated by a guy whose a friend of the club photographer that El Gato punches backstage, in a hurry. He wants to know what happened, which leads him to an insurance investigator looking into the theft of a pretty pricey necklace made of rare South African diamonds (there’s a chapter set in South Africa about the origins of those diamonds). Seems a security guard was punched out by a woman similar to the El Gato incident. The neclace heist happened an hour after El Gato’s set — two and two: El Gato is the culprit.
Marmor didn’t write the best of these kind of books, but he was a competent professional genre author and we’ve found his work so far, like Hell Cat, entertaining reads.