Jeff Regan, Investigator is a fine, hardboiled detective/radio noir series from the 1940s. Today it's perhaps best-remembered as Jack Webb's last role before Dragnet. After his departure, it continued with Frank Graham filling Webb's formidable (gum)shoes until his untimely death.
Jeff Regan, Investigator debuted on CBS with the title Joe Canto, Private Eye on 10 July, 1948 with Barton Yarborough starring as Canto. The first episode, "Doctor, Lawyer and Indian Chief" was rerun a week after its initial airing with the new title of Jeff Regan, Private Eye. During its short run it would variously be referred to in print as Jeff Regan, Jeff Regan Det., and Jeff Regan Detective in addition to its proper title. Webb took over the role of Regan in the second episode, "The Prodigal Daughter" after which Yarborough continued to occasionally appear as Canto.
Webb and his roommate/creative partner, Richard L. Breen, had made names for themselves on the west coast and within radio circles with Pat Novak...for Hire (1946) produced by San Francisco's KGO. After quitting that show and relocating to Los Angeles, the two created its near clone, Johnny Madero, Pier 23 (1947) which aired nationally, on the Mutual Network. However, Johnny Madero was a summer replacement series and did not continue after its short season. After freelancing for a spell, Webb was approached by CBS about creating a new series, which led to the creation of Jeff Regan.