I believe that this is one of Elizabeth Montgomery's best performances in a movie, and I have seen most of her movies.I saw this for the first time on television when I was around fourteen, and I was so scared.I watch this movie every now and then, and I still enjoy it very much.I know that these days that this movie would probably not scare people too much.That just goes to show that the public movie and television audience has seen too much graphic violence in the last thirty years or so.I love movies that do not show the graphic details, you let your imagination do the work for you. The cast in this movie was top notch. Jess Walton, who played the sister in the story was very good, even though her part was rather small. She also played in a terrific made for television thriller around the same time called You'll Never See Me Again with David Hartman.I got the biggest kick out of Eileen Heckart's performance as the housekeeper. Eileen was so good as a lady with a very bad disposition.George Maharis who played the husband was quite effective.This story obviously had a lot of so called mistakes in the plot, but I love the movie anyway. I highly recommend this movie to people who love a good thriller without graphic violence.I gave this movie a vote of seven.