Broderick Crawford was a tough, grouchy private detective who worked for firms in the diamond industry. He worked out of New York City. Ray Hamilton was his handsome young associate.
The show was 30-minutes long and was syndicated. It was on in the early 60's. It lasted one season.
The production company was ZIV, which did Broderick Crawford's very successful previous show "Highway Patrol". "Highway Patrol" was on for four years beginning in 1955 and then played in reruns forever. ZIV's other shows included "Sea Hunt" and "I Led Three Lives".
The theme song of "King of Diamonds" said "he's not saying 10-4 now, he's romancing the queen. He's the king. King of Diamonds."
Crawford always said 10-4 (or out) when completing a radio transmission on "Highway Patrol".