After all the searching I've done on the web, I'm pretty sure that the actor who played the crazed killer is John Baragrey. I've reviewed all his movie credits and none seem to fit exactly. I'm wondering if what I saw was a 1-hour episode of a TV series. His credits show "Suspense" and "Thriller" TV series. Has anyone seen these shows and does my description of him playing a Jekyll and Hyde kind of crazed killer ring a bell?? This may explain why I've never seen it again on TV since the 70s. Thanks for all the help!!