Twenty-seven year old James Francisus ("Naked City") played Russ Andrews, one of the firm's top detectives. Russ Andrews was a Yale graduate and had been an infantry captain during the Korean War. Russ had obvious breeding, class and high intelligence. (James Franciscus really was a Yale grad, who was there with Dick Cavett. Cavett said everyone at Yale thought Franciscus would be a star. Francisus had the lead at Yale in a musical version of "The Great Gatsby", which landed him Hollywood offers).
Thirty-seven year old James Philbrook ("The Islanders") was Steve Banks, the firm's other top dog. Steve was beefier and much taller than Russ Andrews. He was also less cerebral and quicker to use his fists. Steve had been a cop who walked a beat. He had come up the hard way.
Mary Murphy ("The Wild One", "Crime and Punishment, U.S.A.") was a beautiful secretary who sometimes worked undercover. (Mary should have been a full partner with the guys, but this was 1961.)
Guest stars included Lee Marvin, Rhonda Fleming, Mickey Rooney, Dennis Hopper, Jane Wyman, Dina Merrill and Joanna Barnes.
The series was created and produced by Michael Garrison ("The Wild, Wild West"). The executive producer was Richard Irving, who developed "Columbo" and "The Six Million Dollar Man".
This Universal show followed in the footsteps of "Checkmate", which had started the preceding year. Unfortunately, the stories and characters weren't as compelling, despite top talent in front of and behind the cameras.
James Franciscus was the first choice to play "Dr. Kildare", a role he was born for. But Franciscus was already committed to another potential series, perhaps this one. Ironically, "The Investigators" was killed in the ratings by the first season of "Dr. Kildare".
James Franciscus also might have had a longer run on "Naked City". Francisus starred the first season (1958-59), when the show was 30 minutes long. A year after "Naked City" was canceled, ABC surprisingly decided to bring it back as an hour show, but Franciscus had other contractual obligations at that point.
A decade after "The Investigators", James Franciscus was excellent as another top insurance investigator, the blind Mike Longstreet. Stirling Silliphant, who had worked with Franciscus on "Naked City", was the creator and executive producer of "Longstreet".