Fade To Black

Description for FADE TO BLACK by Robert Goldsborough:

Whether it's a case of soda or a case if industrial espionage, soft drinks have never been Nero Wolfe's cup of tea. So only with great reluctance - and considerable prodding from Archie Goodwin - does the legendary sleuth agree to investigate the apparent theft of ad campaigns for Cherr-o-key cola. Stealing soon turns to murder as a young executive lies bludgeoned to death in his trendy Greenwich Village apartment, the carpet stained darker than cherry cola. Now Nero Wolfe is back in inaction - which means his faithful legman, Archie, is running in overdrive - to find a killer before someone else in the fizz biz gets popped.

This is #5 in A Nero Wolfe Mystery.