Made for TV movies of the 80's
I believe this was a made for TV movie made sometime in the 80's. It was about two detectives searching for the murderer of a family who seemed to vanish into thin air. The grandfather of the murdered family sat in his rocking chair for years staring at the remains of the house and barn waiting for the son to return home. He had discovered a secret room below the house where the killer had hidden until the search for him had ended and then emerged and snuck away. It turns out he has been hiding in a mental institution all these years. The detectives track him down through an out of town subscription to the local paper.
I think Walter Brennan might have played the grandfather.
