Ghost Corps was a 1930s radio show that featured K. C. Smith, one of a group of free-lance diplomats operating in the near and far East. Smith's usual beat was the Middle East -- its dark alleys, mosques, and bazaars -- as he worked to bring down various warlords. (I'm afraid the show might not be very PC.)
The show is especially recommended for fans of such pulps as Adventure and Oriental Stories.
Enjoy these two thirteen-part episodes, "Knives of El Malik" and "Prayer Rug of Nana Sieb."