The Casebook of Gregory Hood
The Casebook of Gregory Hood, starring Gale Gordon in the title role, took over where Sherlock Holmes had left off. Sponsored by Petri wine, it used the same "weekly visit" format and the same team of Anthony Boucher and Dennis Green that had written The New Adventured of Sherlock Holmes.
Gregory Hood was modelled after true-life San Francisco importer Richard Gump, and many of the stories revolve around a mystery surrounding some particular imported treasure.
Hood's sidekick Sanderson "Sandy" Taylor was played by Bill Johnstone.
The show aired from June, 1946 through August, 1950. There were an additional couple of shows aired in October 1951. Hood and Sanderson were played in later episodes by Elliott Lewis and Howard McNear, respectively.
You can find more episodes in the Ear Benders section.
Here is a sample of the online episodes currently available at The Old Time Radio Fan: