Murder is the Pay-Off, by Zenith Brown (writing as Leslie Ford) (epub/Kindle/pdf)

"One of the beat mysteries of the year." -- Providence Journal

When an innocent young woman finds herself knee-deep in gambling -- and up to her beautiful neck in debts -- there's apt to be trouble.... And trouble is what Janey Blake had plenty of. She had written a pile of bad checks. And she was fighting to keep her husband from the arms of another woman....

But other people had trouble too. Doc Wemitz, for example. He was afraid of something. And apparently he had reason — for one night someone bashed in his skull....

That was the same night that Janey hit her first jackpot in months — and found a gilded coin that a desperate killer would stop at nothing to retrieve.