Curtains (1983)
(https://vignette.wikia.nocookie.net/evilbabes/images/7/7e/Patti_O%27Connor_reveal.png/revision/latest?cb=20180309061737)
Not sure why some people think this is a bad movie. It's not amazing or anything, but it is decent, and has two of the best actresses in horror movies of all time: Lynne Griffin (Black Christmas) and Samantha Edgar (The Brood).
(https://pbs.twimg.com/media/EXq6CAiUwAIxMCt.jpg)
Also, this sequence is quite cool:
https://youtu.be/TvHCgH1XoYE