Back in the 70s, there was a very popular and acclaimed TV movie about the case that starred Luci Arnaz and Efrem Zimbalist Jr.Are you sure about that? It's one of the most infamous unsolved murders and it's hard for me to believe that some movie, that didn't even make back its budget at the box office, is the reason for that. There was also a video game and multiple books made about the case years prior to 2006.
http://www.imdb.com/title/tt0073897/