It's listed on the wiki page for Unsolved Mysteries, but claims the airdate is unknown. I don't remember this case ever been aired at all though. Was it?

http://unsolvedmysteries.wikia.com/wiki/Dorothy_Jane_Scott

The case doesn't sound familiar. If it had been on UM, the Official Unsolved Mysteries Facebook page would know. If it was never featured on the show, then it would mean the case was erroneously added to UM Wiki.

It sounds familiar to me, but I can't state for sure that it was on UM and not a different true crime show.