In addition to Janssen, the series had other recurring characters. Mirroring Diamond's history with the New York Police Department, the radio version featured his friend, police Lt. Walt Levinson (often played by Ed Begley, Sr.), and on TV, veteran actor Regis Toomey, portraying Diamond's former superior, Lt. Dennis "Mac" McGough, came aboard in the first episode, which aired in July 1957. Toomey then appeared intermittently in seven more, including “Snow Queen,” the final episode of Season 2, which aired on June 26, 1958. Radio's version also gave Diamond a steady girl friend, wealthy socialite Helen Asher (played by Virginia Gregg), a story arc that was neglected by television until the first episode of Season 3, when Diamond meets fashion designer Karen Wells, played by Barbara Bain. But this may have created a conundrum for the producers, since radio's Diamond was also an unrestrained flirt, and Powell's character often shamelessly ogled his beautiful clients before returning to Helen each week. In one TV episode, “Soft Touch,” Karen catches Diamond about to two-time her, and after five episodes, the “steady-girl-friend” arc had disappeared, with Diamond once again playing the field. When he first reached Los Angeles, Diamond had no history with the local police, and his encounters with them are often contentious. In Season 4, Russ Conway was cast as Lieutenant Pete Kile for five episodes, and their relationship soon turns to one of mutual respect, if not always warmth. The omnipresent Sam entered the picture (at least partially—viewers never saw much of her face) in Season 3 and remained for the duration of the series. She was played for most of Season 3 by Mary Tyler Moore in her first regular series role, and later replaced by Roxane Brooks.