The Scarlet Button

The Scarlet Button is a 1944 mystery thriller novel by Anthony Gilbert, the pen name of British writer Lucy Beatrice Malleson. It is the fourteenth in her series featuring the London solicitor Arthur Crook, one of the more unscrupulous detectives of the Golden Age. It was published in the United States, initially under the same name and later with the alternative title Murder is Cheap.

Synopsis
James Chigwell a prolific blackmailer is discovered bludgeoned to death. The murderer may be any one of his large number of victims.