The Fifth Key — George Harmon Coxe

An old friend of Kent Murdock's is murdered, leaving him to take the fall

It's been two years since Kent Murdock saw Sheila, and it only takes a few minutes to remember her flaws. While the Boston newspaper photographer was away fighting in the European war, Sheila's cold ambition took her out of the newsroom and into the studio, to write a radio show that's about to land her in the big time. The wallflower he once knew is now the center of attention -- not all of it pleasant. One night Murdock follows her home for a drink. It proves to be a deadly mistake.

A drugged bottle of Scotch knocks Murdock out, and when he comes to, he finds Sheila dead, strangled on the floor. The Scotch -- the only evidence of his innocence -- is gone, and Murdock is the natural suspect for the beautiful young writer's death. Which means he's going to have to find the killer himself.