Late 50’s, Early 60’s spy movie with the word “crooked” in the title

Movie, maybe in black and white, late 50’s or early 60’s, about an undercover person living with a wife in U.S. About to be identified. He runs with the wife and I remember them running down a railroad with a cane or stick. It seems like it was the actor who played Atticas Finch in To Kill A Mockingbird but I am not sure. The title had the word Crooked in it I think. Something about the childhood rhymn “There was crooked man who had a crooked smile who walked a crooked Mile. . . I watched it on TV with my mother when I was young. I may be saw it in black and white because our TV was black and white.