Name the character: "Just one more thing"

Television detectives in the 1970s had their signature moves down to a science. Some sucked on lollipops, others had theme songs, and a few managed to solve crimes while looking like they'd rather be fishing. But one rumpled detective in a wrinkled raincoat perfected the art of the fake exit, always managing to remember that one crucial detail right as he reached the door. Which character made this particular phrase his calling card?