I remember watching The Fugitive on ABC on Tuesdays at 9 pm central time. I read that the reason it was canceled was that David Janssen tired of playing Dr. Kimble, not because of the ratings slipping as suggested here. I also read that the show's creator Roy Huggins had never heard of the Sam Sheppard case until yeas later. This means any resemblance to The Fugitive and the Sam Sheppard case was coincidental. I had never hear of any real life case similar to The Fugitive until A & E carried re-runs and I mentioned it to a co-worker who was from Ohio and he said that The Fugitive reminded him of a murder case there.
Until the last episode of M*A*S*H* the 2 part finally of The Fugitive was the highest rated TV episode of all time. The 2000 remake did not do as well in the ratings an ended after one season. There were posters referencing the Sheppard case on the 2000 version of The Fugitive.